Today I heard from Daniel Stone who is one of the people working on the R500 reverse engineering. At this point they are still in the early stages of this new driver but within a few weeks they hope the register dumps will become useful. Daniel stated that within a week he hopes they'll be ready for a Wiki at FreeDesktop.org and to throw up some code. So far their development efforts have only been powered by a Radeon X1900 and a Apple MacBook Pro, but soon will be looking for the community to help out (I have already promised them quite a few card dumps). So within a week or two there will hopefully be some new information about the ATI R500 reverse engineering!