Have a look at
Helmet camera | Sports camera | Head camera | Helmet cam | Bullet camera. I bought the HD720/DVR system. They have some full HD cams available now as well.
There's a couple of my vids on this page if you wanna have at look at the quality I get with the HD720:
http://www.pprune.org/private-flying...videos-29.html
I did have to modify the microphone to get sound though. I was placing it in my headset but it was so high gain that the volume level in the aircraft caused it to cut-out.