I've seen hub level/dropout camera mounts. Mostly used with the smaller cameras like the GoPro Hero 5 or discontinued Polaroid cubes.
I'd be cautious about a clamp mount on a seat stay, especially carbon fiber. I do mount a Cygolite Hotrod on the seat stays of my carbon fiber bikes, but those are featherweight lights with rubber band mounts. Even a small camera would need a more secure mount.