thats what the 4890 x2 was, it wasnt released because nvidia's best beat it by a fairly large margin.
This time, I think its gonna be really tough for nvidia to beat the current cards, let alone the reserve card, though they have done it before, which was my point.
Its currently between $600 and $700, but like I said before, AMD has hinted that they are prepared for substantial price decreases when nvidia's new line drops.