Support for TrackIR is present in many racing simulators (from the RACE/CMR/GT series, Live for Speed etc. and almost every other one which has the driver's position). Well, about a third have support for 6DOF, and then it's exactly like that Wiimote demo, including the depth.

As far as I know FSX uses trackIR 6DOF just like any other trackIR enabled game, while 6DOF is nice and adds a lot to immersion it does not make the image pop out of the screen and appear to float out in front of you. Did you actually see the video linked with the targets floating out in front of the screen?

Seriously, I've seen it a few times already. Again, there is ZERO innovation in that. Do you understand what geometry clipping means? Watch it again... now focus on what the devide does: track the goggles' position and rotation. Ok, now think about it, and try to guess what TrackIR does... yep! same thing! EXACTLY the same thing. Do you like the targets feeling as if they were popping out of the screen? that's fine! Now does that tracking offer anything new? nope. Nothing new at all.

Exactly!

Well, there is something cool about that demo but it's not about the technology, which is equivalent to any other headtracking device (but WAY less expensive).

The cool part of that demo is that it was programmed to use much larger movements (more than two meters left/right and close/far), which are impractical and unuseful in a normal game with a cramped cockpit, at least because almost every simulator doesn't want (?) the users to look over e.g. the engine hood in a Fw-190.
An added bonus for that demo: it used extremely simple graphics, and that allowed it to be extremely responsive, it tracked the head (and the graphics engine responded) with at least 60 updates per second; we're lucky to get 60FPS in Sturmovik (on the highest AA/AF) or FSX, and definately the TrackIR input is displayed with a significantly larger lag (I'd say 0.1 to 0.5 seconds) which ruins the immersion. TrackIR4 has 120 updates per second, but they're kinda wasted.