VR Zone heard from one of their sources that the reference card of NVIDIA's G92 mainstream GPU uses a single-slot approach and is 9" long. That's about the same size of the GeForce 8800 GTS.
The PCB version is P393. The 1ns DDR3 memories are arranged in 16Mx32x8PCS array. The card has outputs like HDTV, HDCP, DVI, but no display port yet. Expect some interesting PCB and cooler designs from the card makers at launch.