TrackIR and variants are quite popular for simulator type games like flight simulator or truck simulator. They let you look around in the game just by moving your head.
Hm. I haven't really looked too deep into TrackIR, but I always thought it tracked your head movement to simulate head rotation within the game. So you could look around more naturally. The linked Wii "tracking" demo used the tracking to find your position relative to the display to change the rendered perspective accordingly. Does TrackIR also allow this?
As a TrackIR user, it feels to me like it should be possible to do something like this with the 6dof headtracking data from TrackIR, but basically nobody uses a 1-1 mapping that would produce a camera trick like this.
TrackIR DOES do this. In flight simulator, with full 6dof, you can move your virtual head around and look under and around things
In my TrackIR config, I move my head left an inch, the projected head moves 6 inches. This is more useful than a even mapping in practice, but solidly breaks the 'looking through a window' illusion.