RE: My Dream Game
There are already head-trackers that can do some of that, though obviously you're limited to a degree by the technology since not every game will support it and the fixed screen places its own limitations on the motions you can have before you're no longer looking at the screen past a certain point.
TrackIR is the most notable one and has been around for ages, though there are others out there that I can't speak to the performance of. I've never used any head-tracking setups myself but definitely would consider trying one out.
EDIT: I don't know if you care about Morrowind, but OpenMW has a usable controller interface as of last time I tested it. The others are definitely not anything I'd care to play with a controller (or at least not a traditional controller; Bethesda's VR titles work really well).