Same here. I read in another thread that you can push the power button to make computer to sleep and wake it up by pushing it again. The normal screen will come back. Unfortunately, my motherboard is Z68p and I haven't fixed the CMOS reset issue so I can't wake up my computer without a reboot. When I tried to do a clean install by Unibeast with 10.8.2 ML, I can't reach installer but stuck at this white screen hell. Yes, I know the deleting ATI6000Controller.kext trick but it didn't work this time. Without 10.8.2 ATI6000 kext, I can't even reach the white screen and stuck at Apple logo and the roller stopped spinning. After checking with -v, I found the booting process stopped at "lnx2mac".
I tried to replace it with old ATI kext from 10.8.1, same shxt. So I am stuck in a situation: can't boot into my original system (white screen), can't reinstall 10.8.1, and can't reach installer to do repair permissions on the modifications I made in original system. Now I am considering to change a new graphic card (using ATI6850 right now), or just quit using hackintoash and access my files throughtput Macdrive from a PC.