I've seen the eMagin HMD used for visual telepresence. This guy drives a dune buggy and teleoperates a robot using an hmd with head motion controlling a camera system. The eMagin is about $1K. The tracker on the eMagin drifts like crazy though so but a WiiMote tracking would probably be good enough for many applications. Here's a another cool video .

I've seen the eMagin HMD used for Augmented reality... Actually more like visual telepresence. This guy drives a dune buggy and teleoperates a robot using an hmd with head motion controlling a camera system. Here's a another video that betters explains what he's trying to do.