Current Hackintosh Install OR a any Mac + USB drive
Mountain Lion DMG (No lazy, I'm not giving you a link!)
As a precaution, if your not experienced, I would have a Windows install on another HDD incase you need to add/remove a file.
OK, let's begin!
1. If you are using a USB drive, format it with Mac OS Extended (Journaled) and in options select "GUID xxxxx". If you don't have a USB, open Disk Utility, and select your Hard Drive. We'll call it MHD. So select MHD, and go into Partition. You'll see the resize lines in the corner. Resize your drive by moving them around. Hit the plus button. Name the new partition Installer and make sure it has about 8GB free. 7.99 should work too.
2. Mount your Mountain Lion DMG. It should be called "Mac OS X Install ESD". Then open Terminal. Just search it in spotlight. Copy and paste this into Terminal and hit enter:
defaults write com.apple.Finder AppleShowAllFiles YES && killall Finder
3. Double click the Install ESD on the desktop. There should be a slightly washed out file called "BaseSystem.dmg". Double click it. It should mount on the desktop.
4. Fire up Disk utility again. Select your USB or your Installer partition and hit restore. Drag the Base System from the side into the source box, and the partition or USB onto the destination:
And hit restore. It should take about 5-10 minutes.
5. After it is done restoring, you should have two "Mac OS X Base System" on your desktop. You can right click them and hit get info to see which one is your partition or USB. Eject the other one.
6. Now open up your USB or partition. Go into System>Installation. There should be a file called Packages. Delete it and make a folder called Packages. Then open up Install ESD. Copy everything in it's packages folder onto the folder you just made. This will take about 20 min. Or less. Or more.
7. Your almost done. Time to make your partition/USB bootable! Download this file: http://min.us/mnBar8r9L
8. Double click the installer. Make sure the install location is set to your drive. Ignoring everything else, scroll down and select 1 smbios ( I used the latest Mac Pro)
8.5: Copy the downloaded installer onto the installer
9. After that install, copy any kext drivers you use on your current install (internet, graphics, etc) onto the installers S/L/E AND copy them to a folder on the usb drive/partition. (e.g I had a folder called Kexts on my Installer drive). Then copy the file "mach_kernel" from the Install ESD onto the drive/partition on root /mach_kernel
10. Reboot. Boot into your partition or USB drive. For the kernel flags, do -v.
11. It should boot into your Lion Installer. Navigate through, and hit install. When it completes, DO NOT RESTART. Open up Terminal : Utilities>Terminal, and type in the following:
cp -r /Kexts/ "/Volumes/zzzzzz/System/Library/Extensions
REPLACE THE ZZZZZ with the name of your mlion hdd. If you installed to a drive called "Macintosh HD" it would look like this:
cp -r /Kexts/ "/Volumes/Macintosh HD/System/Library/Extensions
This will copy the drivers onto your Mountain Lion install.
12. Boot your USB drive again, but don't choose the installer. Choose your newly minted Mountain Lion install. It should boot with your drivers like graphics, internet, etc.
13. Setup, blah blah blah. Now open up your installer. Go through the same installer you copied. This will enable booting from the install, and not using the installer to boot.
14. You can trash your installer now if you want.
Note: This is my first guide so if I forgot a step or misspelled something tell me, don't flame me!