As posts here indicate, the big features required in a top of the line DX camera will be an AF system equivalent to the D4/D800, a buffer holding 25-30 frames or more, and a frame rate of 8 fps or faster. A rear AF button is a given - as is a quiet mode. I'd expect to see 24MP - maybe 32 MP or more but megapixels are not the critical factor. Put it at a price point of $1999.
I'm expecting at least one Wow feature. Perhaps an ultra fast frame burst mode or something similar that does not drop the mirror while recording a multiframe burst.