It's possible, but I doubt it mate, with 28nm silicon in such short supply I think it will be quite some time before we see any sort of price drop on standard 680's let alone your 4Gb cards.
You will insist on taking early adoption to the next level I'm sure it'll be fine, and these 690 4GB cards are still 2GB per GPU so they'll be stunted in that regard for high res stuff.
Thanks for showing this man! I was about to buy a gtx 480 but now I will wait a little, maybe the 500 series will drop in price after this announcement!
I received an Nvidia branded crowbar today. Writen on the side is "For use in case of Zombies or..." Wonder if it's related?