While at a local supercharger tonight another model S pulled in. (That was a first for me as I've never had anyone there when I was.) Despite it being dark I could see the exterior rearview mirrors were missing. Got to speaking with the driver and learned that he'd removed the mirrors and replaced them with cameras. Sure enough, as shown in the picture, there were tiny, aft facing rear view cameras sticking out of the structure that once supported the left and right rear view mirrors. The camera on the left fed a small monitor mounted inside the cabin on the left side of the dash while the one on the right fed another monitor mounted on the right side of the dash.