We mantioned this in our review a couple of time salready, but there will be 4GB versions of thee GeForce GTX 680. Gainward is the first to make mention that they are working on a 4 GB variant.
Actuallty Swedish retailer Komplett.se has already listed it for 5,995 Kronor (US $878.7), considering it is a pre-order price I doubt the final price wwill be that high though. The card is furthermore the same as the 2GB model, below a photo.