ASUS is working on a dual-GPU graphics card codenamed the ASUS MARS II, pairing two NVIDIA GeForce GTX 480 chips. The MARS II follows the first MARS card of 2009, which packaged a pair of GTX 295 GPUs, but updates things with a couple of NVIDIA Fermi chips.
Our source at ASUS couldn't tell us any specific hardware details, beyond showing us these PCB boards (which you can bet will sprout some significant cooling systems by the time MARS II launches), but from them we can tell there's an internal SLI connection between the two GPUs and each will have its own dedicated memory. Together, the two Fermi GF100 chips will give the MARS II a full 960 CUDA cores.
To give an idea of the power requirements such a board will have, you can see the three separate eight-pin power ports in the top right hand corner. No word on release dates or pricing at this stage, but the ASUS MARS II could well be the most powerful Fermi card around.