I updated my hack to 10.7.2 today and watched her boot up to a black screen. More accurately, the monitor went to sleep immediately upon loading the OS X GUI.
The interwebs indicated that the EFI string I’m using to inject my NVIDIA GTS 250 graphics card was causing the problem.
Sure enough, I removed the EFI string and was able to boot into the GUI, albeit without graphics acceleration.
I was able to add pseudo-acceleration by adding the Chameleon key to my com.apple.boot.plist, but it was choppy and slow.
Finally, I returned to my old way of graphics injection by throwing the NVEnabler.kext (64-bit) into /System/Library/Extensions (the NVEnabler devs claim that it should work in /Extra/Extensions as well, but I tried that first and it didn’t work).
TL;DR: To get my NVIDIA GTS 250 graphics card to play nice with OS X Lion 10.7.2, I had to remove the EFI injection strings from com.apple.boot.plist, remove the GraphicsEnabler plist key, and add NVEnabler.kext (64-bit) to /S/L/E.