Still a lot in the air. This is from the latest monthly "Best Graphics Cards for the Money" article from TH:
"As for other news on the video card front, unfortunately, we don't have our fingers crossed for new graphics architectures in the last couple months of the year. There are a few reasons for this, but three stand out most prominently. First, the current generation of cards is more than capable of handling today's most demanding games (especially with companies like id delivering low-spec console ports like Rage). It's a good thing developers like Dice can still demonstrate the PC's place in gaming with titles like Battlefield 3 (see Battlefield 3 Performance: 30+ Graphics Cards, Benchmarked if you missed it two weeks ago). Second, with no major update to DirectX being discussed, there's no new API to drive interest in new graphics hardware. Third, next-gen products like AMD's Radeon HD 7000 series and Nvidia's Kepler are still subject to manufacturing kinks in TSMC's 28 nm node, and it looks like it will take some time to get the bugs out of that process. At this point we wouldn't be surprised to see some new products manufactured using 40 nm lithography, and we've heard rumors to support that. There's nothing concrete to report yet, though, and, for the first time in a long time, it looks as if we won't have any major announcements to take us through the end of the year."
I'd expect no sooner than the latter part of Q1 2012 but that's just speculation.