FreeTrack once had a support for virtual joysticks. (Still has if you happen to have a really old OS)
Which was realized with PPjoy which is no longer in development. And the website is down, too.
But there is
http://vjoystick.sourceforge.net/site/ with at least the same capabilities.
It would be really great if that would be supported so you can use it in games which don't have TrackIR support.
And it this kind of support was kinda already in ... it just used a different program