The best i can do is that it will be after Tesla and Quadro models.
The impressions that i am getting is that 28nm supply is still very constrained. And Nvidia is is absolutely no hurry to release a gaming chip to beat the GTX 690. What i heard is that it will be Nvidia's top gaming GPU for the next 6-9 months.
-- of course, with such a mediocre offering from Nvidia's competitor and no real chance of a refresh, Southern Islands is next year. So it is logical that Nvidia's next gaming chip will be next year - after the Q4 release off K-220; big k for Tesla.
Evidently the GTX 6x0 is selling well and the demand is exceeding the supply - even with the GTX 670. The impressions that i got is that if TSMC could produce *double* the amount of chips, it would still not be enough for the immediate demand.
i also understand that these issues are getting better and will get better over time, but it is logical that a 7.1 Billion transistor chip will also be in short supply when it is released and the first ones will be reserved for Quadro and Tesla.
So ... 6-9 months ..