NVIDIA already got its Quad SLI running and now ATI decided to create a Quad CrossFire product.
ATI has decided to combine two Gemini boards that feature two R590 chips each. You're reading it right, we're talking about dual R590 boards working together, or a Quad GPU powered ATI product.
The final physical design is far from being completed but ATI's Gemini X1600 is a concept where two chips fit on a single PCB. However, in order to create room for two 256 bit memory interface and quadrupled power consumption and heat dissipation - you need to be very creative. Enter creative engineering.