A bit of a flop with their original 6800 series of dual cards, ASUS has upped the stakes and, due to the popularity of the 7800GTX, possibly created a must-have for enthusiasts. No, this isn't an SLI solution. This is an actual PCB with two GPUs on the card itself, letting you have SLI performance in a place where space may not let you. Although it hasn't left development yet, and details aren't complete, it's still an awesome thing to see. It supposedly will allow you to use SLI in boards that do not natively support it. ASUS choosing the 7800 GPU for a finished product is a good one, considering the 7800 has become much more popular and offers better performance with less power draw. Double the GPU and you double the power draw.
Like the cancelled 6800, this card will draw a lot more power than a single 7800 as well as requiring more room, but eventually you open up the possibility of SLI with dual cards, giving you, theoretically, 4 cards. This hasn't been done in practice yet but nVidia has stated it is possible. Let's hope ASUS can get this one off the ground and our hands this time.