Looks like GK110 should be about as powerful in gaming as the GTX 690 dual GPU. I think I will be glad that I waited it out.
It seems from the article that they have been tinkering with the design these past months. Maybe they are working to improve efficiency, much in the way that they improved upon the efficiency of the 480 when developing the 580, like Kepler Revision 2. If so, and I am just pulling this all out of nowhere, then I would expect them to jump up to the GTX 780 nomenclature.