Since the solutions presented here are different than mine was, I cant really comment on them, although they seem very workable to me.

My "gravity leveler" code is the heart of my current game concept (sort of a "wipeout" inspired racing game). It will be pretty much finished once I can finally fix the collision problems with the vehicles sometimes "clumping" together and becoming stuck. At that point if it is still needed (or if I lose interest), I wouldnt mind posting my solution here also.