Yeah I have been pulling out my hair with this issue as well. So far Andy cd (ver 4 and 5) have been successful in allowing me to install 10.6.3. I can use ##### to install the proper kexts. However If I attempt to update to 10.6.7 or 10.6.8 I can no longer boot up, neither in safe mode, verbose or both at the same time. I have been seeing a lot of people are having similar issues with their video card being a xfx5770 (which I have in my rig).
I too tried #####-##### methos but unfortunately the only version of ##### that would work is the legacy version which still ended up with an inability to upgrade.
It might be a good idea to list the hardware you are using, this may allow more people pinpoint the problem.
I ended up swapping my LE for an M PRO. But I got further by switching video cards and installing the stuff that I needed to from ##### that way. I suggest installing the install package, but not restarting right away. Then you open MB and install the stuff you need to from there. I think is one thing that helped.
Also, when I tried GraphicsEnabler=No on boot, I was able to get past the white screen where it freezes. So if you're getting that, then try that boot option to avoid a freeze. Your stuff will move very slowly once you do this, but it will at least boot and then you won't have any issues for a bit while you try to fix everything. These are the options that helped me, so hopefully they help you, too. Good luck. If you have any questions, just post here and I'll see if I can help.