The hardware does it already.
Elite Dangerous only exposes Two axes for head tracking using this kind of technology. Yaw and pitch. There are reasons for that, but I really don't want to go down that rabbit hole here. The Blue Peter headtracker thread has covered it in depth.
The USB game controller calibration thingy in windows shows Three working, Roll, Pitch and Yaw.
Other games / software could theoretically use all Six degrees of freedom.
Would probably require some additional code to handle the Three extra axes.
I don't know if it's simply adding a few variables and cleverly reusing the existing code or adding whole new sections of code. We are pretty tight on memory but properly optimised code should handle it no problem.
But that is more Pocketmoon's area of meddlement.
