I've always wanted to video my own hunts and I found this searching the web. It's basically a "helmet cam". They show a bowhunter using it. Its a little pricey but its very small and it looks like it would work better than anything I've seen so far. You could mount it to the bill of your hat or to your bow or bow arm.

http://www.viosport.com/explore/index.php?page=sports_hunting