Both Bushnell and Burris make laser rifle scopes that are battery operated. Neither of them are illegal. They simply combine a rangefinder and scope into one.
It's not illegal to attach a camera to your rifle. The problem is; where do you attach it. you could strap it to your barrel, under side. It certainly would throw off the balance. But why? Just get a new Digital 1080i Flip Camera. Takes still and video. Good quality, small, light, and can be attached to a small tripod as well. They are pretty inexpensive.