Meet the Robotic 360 Pan and 180 Tilt System from SuperDroid Robots: a wonderful system that adds 360+ degrees of pan and over 180 degrees of tilt capability to your camera. It has two sail winch servos with gears and other components to move your camera reliably. The servos can be controlled using a RC controller.
The unit weighs 2.6 lb. Its brackets and body are made mainly of aluminum. More info is available here.