Any reason why you're looking for one? Performance difference between the GTX560TI and the GTX570 isn't that much, but the power draw is noticeable. Making a GTX560TI off the same chip as the GTX570/580 will be great for Nvidia due to die harvesting, but the performance per watt won't be as good as the current GTX560TI. Many of us weren't impressed with (rumored?) specs of this new chip.
To answer your question, I don't believe we've heard. I think they are readying it for when AMD launches their new 7 series. If this is so they have something "new", then expect it late Nov/early Dec when the 7 series comes. Otherwise we might not ever see it.