In my opinion Bill, Nikon will never produce a pro camera with "scene" options, so I don't think it's a replacement for a D300s. However, I do believe it was always intended as a replacement for the D90. That way the Expeed2 processor has two cameras (D3100 & D7000) as a proving ground and different sensor pixel sizes too.
It's all hypothesis of course and yes fun also. My guess is that it will be a D400s with all the attributes of the D7000, the ruggedness of the D300s, upgraded video (yuk)but with the 51 focus points and some new gismo's to claim as "revolutionary". It's all about the battle of the brands.