The rumored GTX350 is so impractical there is no way it will be made anytime soon
It's so impractical Nvidia probably has engineering samples that come with an onboard PSU and requires it be plugged directly into the wall socket.
Actually, they'll probably just buy out all the 4870x2's and slap on a few stickers and charge us 900 USD for it. the Nvidia fanboi's will drown them in praise for making such an amazing card and Crysis will release a new patch which optimizes gameplay on ATI cards. All of a sudden the mythological GTX350 will hit 60 FPS in crysis on very high and the ATI 4870x2 will do the same.
The ATI people will laugh and laugh because they paid $400 less and the Nvidia fanboi's will be blown away by the performance of their new "nvidia" card.