I am wondering if it would be possible to include TrackIR as a module of the skyline engine?
This system is used by simulation, serious gamers and has been adopted by some of the big AAA companies (titles such as the Arma games, flight simulators, driving games, combat games and simulators in general).
It allows you to move your head and the free camera turns to where you are looking in your games with up to 6 points of reference (DOF), apparently the SDK is really easy to implement and I think it would be a unique selling point for Skyline..
http://www.naturalpoint.com/trackir/