I've seen others do this, and now that the weather's cooled down a bit, I was able to do some of my own field testing recently. Here's a movie of a GoPro HD Hero in a waterproof housing mounted on Vegas. I used the neoprene harness from an old Garmin DC 20 dog tracker -- works pretty slick.
As you'll see, it's a little Blair Witch Project-ish, but I'm really excited about the possibilities as a dog picks up scent, slows down, and goes on point. I think the viewing angle is wide enough that I'm going to get some pretty sweet covey rises, and maybe some retrieves, too. Combined with myself wearing one, we could have some pretty fun videos this fall.