What I really want to see is a 1gb version of the 4850...
Putting 1gb in it would be a waste of money, as the 9800gx2 vs gtx280 battle has shown memory amount and bandwidth are not so important anymore unless to plan to game at super high resolutions.
Sure 512mb and 256bit buss may be the bottleneck it less shader heavy games, but in those games you would still be getting over 60fps.
If the gtx280 had only 512 mb and 256 bit bus, its performance in crysis at resolutions up to 1600*1200 (possibly higher)
would be near identical.