They said it couldn't be done!!! But after I successfully upgraded my daughter's late 2006 iMac5,1 to Mountain Lion 10.8.4 using HackerWayne's MLPostFactor as seen here http://forums.macrumors.com/showthread.php?t=1325709
I got to thinking that maybe there was some hope for these aging ThinkPads yet. I'll do my best to break down exactly what I did to get Mountain Lion up and running on my ThinkPad T60P.
The trick to getting this all up and running was to be as minimally invasive with the hacks and tweaks that you use, because Mountain Lion Post Factor (MLPF) is already an extensive collection of hacks, tweaks and modified drivers that are aimed at getting Mountain Lion to run on real legacy Macs that have been obsoleted, provided they meet the minimum hardware requirements (64 bit capable processor and at least 2GB RAM). Since I already had to make those upgrades to get Lion running on my T60P, I was ready to go.
Anyway, so here is the basic rundown of what you have to do:
1) starting from your fully functional 10.7.5 install, acquire the "Install Mountain Lion" app and MountainLionPostFactor and the latest Multibeast (5.5.5 at the time of writing) for Mountain Lion.
2) create two more hard drive partitions, each a BARE MINIMUM of 8GB, one called "Install", the other called "ML" (as per HackerWayne's instructions... technically you can call them whatever you want). I managed to install Mountain Lion on an 8GB partition and it is NOT happy. from first boot, it was squawking at me about the startup disk being full, blah, blah, blah...
3) Making sure that the Mountain Lion app is in /Applications, run MLPF, pointing it at the "Install" partition. This is basically doing the exact same thing that XMove from TonyMacx86 does. After it completes, (keeping in mind that this IS a Hackintosh), run multibeast on the "Install" partition, selecting ONLY the bare minimum kexts needed to get the system working (JMicron36x_ATA, ElliotForceLegacyRTC, EvoReboot, FakeSMC, NullCPUPowerManagement PS/2 Keyboard/Mice and AppleACPIPlatformRollback (10.6.
. You'll also need to install VoodoTSCSync if you don't want to have to boot with cpus=1.
4) Reboot and select the new "Install" partition at the Chameleon boot loader. If your computer fails to boot up the first time, it's probably because of tweaks that you made to your org.chameleon.Boot.plist on your working 10.7.5 partition. Temporarily, rename /Extra/org.chameleon.Boot.plist to /Extra/org.chameleon.Boot.bak and proceed with installing 10.9.4 to the new "ML" partition.
5) after successful installation, as per HackerWayne's instructions, under the Utilities menu select "MLPostFactor" and install it on the "ML" partition.
6) reboot back into your functional 10.7.5 partition and install all of the same kexts you installed on the "Install" partition. You will also need to make whatever modifications to your Graphics, WiFi, etc. kexts. For my graphics card (V5250 FireGL) I had to install the AppleACPIPlatForm.kext from 10.6.8 (I think) and add 0x71C41002 to both the ATIRadeonX1600.kext and ATI1600Controller.kext. If you have a different graphics card, you are on your own.
7) Reboot into the new "ML" partition. If it won't boot, double check that you have disabled the org.chameleon.Boot.plist on your main 10.7.5 partition. If you have and it STILL isn't booting, repair disk permissions on the ML partition. If that doesn't work, boot with -v -f.
You can reuse your smbios.plist and dsdt.aml from your 10.7.5 partition. You will need to keep the modifications to the Boot.plist to a minimum and make changes one at a time. If you used any EFI strings, they are not going to work anymore and will probably prevent your computer from booting ML successfully.
Enjoy Mountain Lion!!!
I'm still in the process of sorting out what works and what doesn't. So far I have not gotten the App store working, but all of the hardware that worked in Lion works, including QE/CI!