The only options I know of are the 9600 Pro for $220 and the 9800 Pro for $250. I'd take the 9800Pro, since it's quite a bit faster than the 9600Pro.
OWC has it. But at that point you're really not that far away from the X800 at $330.
Or you could buy the PC version of a card (9600Pro for $50, 7900GT [much faster than any of the other cards mentioned in this post] for $200) and flash it with the instructions from
strangedogs.