There's a new HD Wearable Camcorder available from VholdR called the ContourHD shown
here. I've thought about getting a video camera before but have been really disappointed with the sound. For motorcycles it seems that most just get a howling wind noise and since the mic was on the inside of a watertight enclosure there wasn't much you could do about it. The advertising claims this has been improved with the new model and based on the following video it might be true. If not it certainly would be interesting to know how they recorded the audio.
In any case I thought the video was interesting. Note that it is SD but a 1280x720 can be downloaded.
Video Sample of Road Race
Looks real tempting as far as I can tell.