Thanks - btw, if you can give me some info on the bug report you filed with apple, I can file another one through my rep there.
I didn't file the report myself, so unfortunately I'm not aware of the details. Feel free to file another one, but we still don't really know what the cause is, so it's would be probably be tough for an Apple dev to do much with it at this point anyway.
will this built be available for everyone or only beta-testers?
It will be publicly available, but only recommended for testers. And I probably wouldn't use the term "beta" to describe it's quality, but it shouldn't be too bad. It's not going to be guaranteed to work properly in other words.
And, just as a test, I think that I'm going to include a possible change relating to this graphics problem. It's not going to be a fix per-se, but merely disable some bits of code that I think may be hiding what triggers the driver bug. Performance and graphics quality will suffer as a result of this, but perhaps if enough of you help out then I'll be able to track it down to just the problematic bit of code.