This is a pretty open ended question and since there is little equipment information in your profile I'm assuming it's mostly rhetorical musing.
I guess the simple answer is a DX sized sensor . After that it can mirror the FX features of the D800 - just chop down the D800 sensor to DX. e.g. I want an robust D300 sized body with a MB-D10 like grip with D800 focusing, dynamic range, at least D3s ISO capability, bright VF, 50+ AF brackets, etc. The whole range of features in a better than D7000 sensor.
If they introduce that camera with at least a 24mm FOV equivalent f/2 prime (i.e. 16mm f/2 Nano coated - gold band prime) I'll know they are serious and I'll buy. The other thing that would really cinch the deal would be a 16-80mm f/4 AFS VR lens.
Roger It's still, ISO, aperture and shutter-speed, right?