I found this:
Update from Scott: Ok, I whiffed on this one and gave Cyril the wrong info. The revised 8800 GTS 640MB cards are, in fact, based on the G80 GPU, and they simply have an additional SP cluster enabled internally, giving them 112 SPs and a little more texturing capacity. Because they're based on the G80, these cards do not have the VP2 decoding engine, doubled texture addressing capability, or power consumption improvements found in the G92 and the GeForce 8800 GT. Apologies for the error
HERE
I also found this:
imply put, the GeForce 8800 GT will not be the only model powered by the lovely 65nm-built G92. The Corporation known as Nvidia is preparing to revamp the 8800 GTS after it has received a serious beating from the 800 GT. The new G92-based 8800 GTS will have 512MB of memory, at first and although it will boast a 256-bit memory interface, it will have 128 Stream Processors, same as the G80 8800 GTX and 8800 Ultra.
The new 8800 GTS will have updated (read higher) clocks compared to the G80 version and will most likely surpass the 8800 GTX in performance. The new card will be released in December so as to try and let the remaining 8800 GTS' be sold to unsuspecting victims. The price of the G92 GTS should remain around $399 although somehow $499 doesn't sound odd either (unfortunately).
HERE
So things are very much still up in the air.
