It would have to be a 2 disc game on the cube probably... or everything would have to be compressed a lot and bad looking.
If the game does well on the PC Aspyr will probably do a Mac port, but it would have to be a pretty big success first. Aspyr ports lots of stuff though (erm, and are publishing Stubbs the Zombie! in an unrelated tangent).
(and no, I made and put up that banner out of the goodness of my heart, no money is being earned on it... except by eb, gamestop, and majesco of course)