PCPOP over in China managed to get a hold of a reference designed GTX 280 graphics card and strip it completely naked for public viewing.
From the pictures, it looks as if it will be roughly the same size as the current high-end GeForce 9800 GTX and you will need to hook up one 6-pin and one 8-pin power adapter to make it run at full speed.
Looks like we can expect some benchmark figures any day now.