Heck, 6800 Ultras in PCI-E cost more than 7800 GTs. Some 6800 GTs cost more than some of the 7800 GTs. Video card pricing is completely insane.
I wonder what drives it--are there some people out there who don't shop around at all and who don't do any research who just go out and spend $400 on a 6800 Ultra when a 7800 GT can be had for $330 (or a 7800 GTX for $440)? I hope that the e-tailers end up holding on to their 6800 GTs and Ultras for a long time since no one will want to buy them at their over-inflated prices. Then one day, perhaps two years from now they'll discover a stock of unsold 6800 GTs and Ultras and put them on clearance once they have little value. I can imagine them saying, "OMG, we paid $200 each for them wholesale and now we can barely get $100 for them."
That might be what's holding them back from lowering the prices to where they should be. They cringe at the thought of selling for a break-even price or a small loss. A smart e-tailer would have taken the prices down to $260 by now.