You need to stop by HardOCP to see the updated, hi resolution photos they have coming in from CeBIT of the Asus dual 6800 Ultra card — two 6800U GPUs on a single card???  Outrageous.
Notes on this are that the card uses 512MB of DDR3 (256 per GPU) and will require a special motherboard. Of course we saw Gigabytes dual 6600 require a special motherboard, but it did run on our ASUS SLI board just fine. So time will tell.