It's very difficult to find a laptop that can easily be turned into Hackintosh. As mentioned in our Hackintosh compatibility guide, most laptops aren't good Hackintoshes, because the compact design of laptops makes it very difficult to replace non-compatible parts.
With this in mind, I've compiled a list of Hackintosh-compatible laptops, all of which can run OS X Mountain Lion without the need to replace any hardware. As expected, many of the laptops on this list were also on our previous list for Mac OS X Lion-- after all, the hardware requirements between Lion and Mountain Lion are relatively similar. Most of the guides provided below are from tonymacx86, and have files attached to them. To view and download attached files on tonymacx86, you have to register an account on the website.
Of course, keep in mind that no laptop will ever run Mac OS X as well as a real Macbook. But some can get pretty close.
HP ProBook 4530s ($500-$950)
Hackintosh Ability: The ProBook 4530s is pretty much the gold standard of Hackintosh laptops. Almost every part of the ProBook 4530s works with Mac OS X: WiFi, audio, ethernet, sleep, bluetooth, USB 3.0, the battery meter, the trackpad, and even the SD card reader. Tweaking is kept to a minimum, since the HP ProBook 4530s forum on tonymacx86 has more or less figured out everything for you. If you're looking for a truly Hackintosh-friendly laptop, go with this one. It's even endorsed by tonymacx86 himself.
Unlike most laptops, setting up Mac OS X on the ProBook 4530s is pretty easy. Just install Mac OS X with Unibeast, and then run the HP ProBook Installer to enable sleep, sound, and various other features. For details on this part of the process, check the installation guide linked below.
However, even once you get Mountain Lion working, not everything is perfect. For instance, Bluetooth won't work after waking up from sleep, but screen brightness controls won't work before waking up from sleep. So you'll have to decide which feature is more important to you. Also, Bluetooth doesn't work after a restart (only a cold bootup will make it work), the VGA port is unreliable, and the external microphone doesn't work at all. However, don't let all of these problems with the 4530s discourage you; none of the problems really affect the laptop's usability. In fact, the 4530s actually has fewer problems than most Hackintosh laptops. It just happens that the glitches for the 4530s are better documented.
Resources: Guide to Installing Mountain Lion on HP Probook | Forum
HP ProBook 4430s ($500-$700)
What You Get: The ProBook 4430s is the smaller brother of the 4530s. While the design and most of the technical specifications are identical, the 4430s uses a slightly smaller 14-inch screen. Additionally, while the 4430s can use both Intel Core i3 and Core i5 processors, there aren't any models with Core i7. With such a compact screen, this laptop begs a comparison to the 13-inch Macbook Pro. In most aspects, the 4430s and the 13-inch Macbook Pro are essentially equal. However, the lower price of the 4430s comes with its own costs: remember that ProBooks usually only get about 3 hours of battery life on Mac OS X, while the Macbook Pro tops off at nearly 7 hours.
Hackintosh Ability: The ProBook 4430s lives up to the Hackintosh-friendly reputation of the HP ProBook line. Compatibility-wise, the 4430s is just as good as the highly-regarded 4530s: WiFi, ethernet, graphics, audio, trackpad, battery meter, and bluetooth all work with little to no effort. However, like all ProBooks, the ProBook 4430s has issues with bluetooth and brightness controls, and the VGA port and external microphone don't work.
Resources: Guide to Installing Mountain Lion on HP Probook | Forum
The 4430s isn't a very popular Hackintosh laptop, so there aren't many Hackintoshing guides about it. Fortunately, Hackintoshing guides for the ProBook 4530s (linked above) usually work for the 4430s without any trouble.
HP ProBook 4730s ($800-$1100)
What You Get: The ProBook 4730s is a larger, higher-end version of the ProBook 4530s. Unlike the 4530s, the 4730s has a 17.3-inch screen, so it's large enough to replace your desktop computer. In addition, the ProBook 4730s uses higher-end parts; every model of the 4730s uses either a Core i5 or Core i7 processor. The 4730s also uses a discrete graphics card (the AMD Radeon 6490M) instead of the processor's built-in HD 3000 graphics.
Hackintosh Ability: The ProBook 4730s mostly works with OS X Mountain Lion, but it's not nearly as Hackintosh-compatible as the 4530s. The graphics card in the 4730s (the AMD Radeon 6490M) doesn't work with Mac OS X, so you'll have to disable it in the BIOS. This isn't a huge loss, but it's inconvenient, and it definitely complicates the installation procedure. The 4730s also has problems displaying Mac OS X at the correct screen resolution, since it uses a different resolution (1600x900) than other ProBook models.
Most importantly, this laptop sometimes experiences graphical glitches in Mac OS X, that prevent you from using Mission Control or the Dock. Though it's not hard to work without the Mission Control and the Dock, it's extremely annoying, so keep this in mind. Apparently, you can fix some of these errors by installing "Graphics Glitch Fix" in the HP ProBook Installer and running SwitchResX to complete a "Display Override". Otherwise, everything else (WiFi, audio, trackpad, etc.) should work pretty well. Like all of the ProBooks, the 4730s has problems with bluetooth, brightness controls, the VGA port, and the microphone.
Resources: Guide to Installing Mountain Lion on HP Probook | Forum
Lenovo G470 ($500)
Hackintosh Ability: Setting up Mac OS X on the Lenovo G470 is not totally straightforward. Fortunately, the standard Unibeast installation method works. After the initial installation, all you have to do is run Multibeast once, and then install a few extra extra kext files. From there, almost everything will work properly: graphics, WiFi, ethernet, Bluetooth, sound, trackpad gestures, battery meter, and even the Fn keys on the keyboard. The laptop does not automatically go to sleep when you close the lid, but you can still sleep manually (by clicking the "Sleep" button in the Apple icon menu, at the top-left of Mac OS X). The webcam also works, though it apparently suffers from brightness issues. The only parts of the laptop that don't work at all are the SD card reader and the brightness controls, neither of which is a major issue.
The biggest problem with the Lenovo G470 is the lack of easy-to-follow guides for it. Luckily, the process is reasonably brief: first, install OS X Mountain Lion on your G470 with Unibeast. Download the DSDT file and some extra kexts (linked below in "Post-Installation Files"). Unzip the downloaded archive by double-clicking on it; a folder will appear. Drag the file "DSDT.aml" out from the folder, onto the desktop of Mac OS X. Run Multibeast and select these following options (choose whichever version of Patched AppleIntelCPUPowerManagement that applies for your copy of Mac OS X). Finally, install all of the kexts in the unzipped folder by using Kextbeast. You're done! (If sleep mode doesn't seem to work on your laptop, install Null CPU Power Managment in Multibeast, and use Kextbeast to manually install SleepEnabler.kext.)
Resources: Mountain Lion Post-Installation Files | Mountain Lion installation thread
The "Mountain Lion installation thread" (2nd link) includes some additional details about the installation process. In particular, it shows how to enable speedstepping on the G470 with an SSDT file, which allows the laptop to go to automatically go to sleep when you close the lid.
Lenovo IdeaPad B570 ($500-700)
Hackintosh Ability: With a good amount of tweaking, you can turn the Lenovo B570 into a reasonably functional Hackintosh. WiFi, ethernet, graphics, audio, battery meter, sleep, and the trackpad all work. The webcam does not work normally, though it works with the app CamTwist (this is a common Hackintosh quirk). The SD card reader doesn't work at all. In OS X Mountain Lion, CPU power management doesn't work properly; however, though this may harm performance and waste battery life, it probably won't affect the laptop's day-to-day usability.
Like in the case of the previously-mentioned Lenovo G470, there aren't any good Mountain Lion installation guides for the Lenovo B570. You can install Mountain Lion on the B570 by using a Unibeast USB drive with the MBR patch. Download a DSDT file and some extra kexts (linked below in "Post-Installation Files"). Unzip the downloaded archive by double-clicking on it; a folder will appear. Drag the file "DSDT.aml" out from the folder, onto the desktop of Mac OS X. Run Multibeast and select these following options. Then, install all of the kexts in the unzipped folder by using Kextbeast. Reboot; if you get a boot0 error, follow this guide to solve it.
Resources: Mountain Lion Post-Installation Files
Acer Aspire 5750G ($550-$830)
Hackintosh Ability: All of the essentials of the Acer 5750G, such as WiFi, audio, and the trackpad, work on OS X Mountain Lion without much of a hassle. Neither Bluetooth nor USB 3.0 works in Mac OS X, but they're not exactly critical features. However, the 5750G's discrete graphics card also doesn't work, so you'll have to turn it off in the BIOS (thereby eliminating the biggest advantage that the 5750G has over similarly-priced laptops).
The Mountain Lion installation process for the 5750G is a bit complicated, but the standard Unibeast method still works, so it's not totally crazy. The main problem with the 5750G is that Multibeast doesn't work correctly with it; instead of relying on Multibeast, you'll have to install a bunch of kexts manually with Kextbeast, and make your own "Extra" folder to hold the laptop's DSDT file. Neither of these steps is really that hard, but previous Hackintosh experience is highly recommended when working with this laptop. There's also an option to install a new BIOS for your laptop that is specially modified for Hackintoshes, but this is an optional step, so you can skip it if you're uncomfortable.
Resources: Mountain Lion installation guide
This installation guide only works with specific models of the Acer 5750G. If your 5750G model uses a Broadcom WiFi card or Elan touchpad, it will not work.
ASUS G53Jw - A1 ($1400-$1700)
Hackintosh Ability: If you're looking for a high-end Hackintosh laptop, the ASUS G53Jw is a great choice, as long as you don't mind its relatively outdated hardware. However, the OS X installation process for the G53Jw isn't the simplest, so you'll need some previous Hackintosh experience to pull off this install.
With the right kexts (available in the second link below), you can get it up and running with almost full functionality. Graphics, WiFi, ethernet, audio, Bluetooth, USB 3.0, battery meter, trackpad, the microphone, and even the keyboard backlights all work. In OS X Mountain Lion, sleep mode and the HDMI port in the G53Jw only work if you update to OS X 10.8.1 and install some extra drivers from NVIDIA (details in the first link below). The only thing that doesn't work SD card reader. Card readers are both optional components for a laptop, so depending on your needs, this might not even be a big deal.
Resources: Mountain Lion installation thread | Lion installation guide
Though the second link is only an installation guide for Lion, the G53Jw uses the exact same kexts in Lion as Mountain Lion, so it still works. Be sure to get the A1 model of the G53Jw when following this guide-- the A1 is the only supported model.
ASUS G74SX ($1500-$1900)
Hackintosh Ability: In the same vein as the ASUS G53Jw, if you need a powerful Hackintosh laptop that can serve as a desktop replacement, the G74SX would be a fine choice. The installation process for the G74SX does not involve anything particularly out of the ordinary, but it's certainly not easy-- I would only recommend this laptop for experienced Hackintosh users.
With the right DSDT file and a plethora of extra kext files (available in the guide below), you can get the G74SX running with mostly full functionality in OS X Mountain Lion. Graphics, WiFi, ethernet, audio, battery meter, trackpad, sleep mode, and keyboard backlights all work. As of yet, USB 3.0 still doesn't work properly, and Bluetooth support is unreliable. The webcam works, except with official Apple applications. WiFi support is a bit spotty; it only works with the Wireless A, B, and G standards, but not with the newest (and fastest) N standard. The microphone, HDMI port, and SD card reader haven't been confirmed to work yet. With the exception of the limited WiFi support, all of the compatibility problems with Mac OS X on the G74SX are relatively minor.
Resources: Mountain Lion 10.8.2 on ASUS G74sx from start to finish
There are a lot more compatible laptops in the Hackintoshing world, but most of them use outdated hardware, or don't have a coherent installation method for OS X Mountain Lion. This list is constantly expanding, as I find more laptops that fulfill these requirements. For now, keep your eyes peeled on tonymacx86's laptop forum, as well as InsanelyMac's own notebook forum and tutorials section.