Originally posted by nosnoop and some features that D400 won't be able to match.
I can't think of anything that the D400 'won't' be able to match, except maybe body size... The D300 already has a comparable sensor, LCD, body, weathersealing, and probably better high iso, focussing and metering (my guess, given K-7 specs) and faster ffs. You can pretty much guarantee the next one will have kickarse video too...
That said, i don't really see the point comparing the two. D400 will be basically Pro level APS-c, K-7 is enthusiast. In Australia I wouldn't be surprised to see $1000 price difference for body alone when the D400 arrives.
My bet is for camera of the year is K-7; offers an awful lot for the money, fixes the main gripes with the K20, and puts it in the first portable 'enthusiast' body