Now this is more up my alley. new details on the Asus Mars dual GTX 285 have hit the internet and they are impressive. What you have are two factory OC'd GTX 285s each has its own 2GB of GDDR3 to play with for a total of 4GB for the card.
Internally the memory interface is going to be 512-bit; this is not 2x256-bit interfaces but 512-bits per GPU.
The clock speeds will be 648/1476/2400 MHz for core, shader, and memory respectively.
There is a dark side to all of this though. The Mars Dual GTX 285 be a very limited edition. Asus is planning to only make 1,000 of these and as each one will have a $1250 price tag it will only be for the enthusiasts with a lot of extra cash to throw around.
The rest of us will have to sit back and dream