Baking animations, changin gravity

I already posted in Blender General about something similar.
Im wondering if its possible to vary gravity form object to object, and then bake the results so i can render the animation


the new 2.40 with the bullet engine have a “record ipos” from game engine
in the Game menu ( you make your animation/setup with the game engine,
press P, stop the game engine and in the Ipo window will find plenty of little nice keys, just do Ctrl-A to check the animation)