Imagine the kind of HD magic you could film with a Canon5D MK II mounted on a helmet. The possibilities have not been lost on Hollywood apparently.
Rodney Charters, the Director for Photography on 24 expressed interest in it via an email sent to planet5D. He also believes that it may have been used on Ironman, although he has no confirmation on that. Either way it would make for some interesting fight and POV scenes, not to mention comical situations on set for anyone trying to pass through a doorway with one of these on. [planet5D]