In response to violinists that wanted more freedom of motion while playing, the folks at NS Design have developed a balanced shoulder rest system for their electric violins. A flexible, foam-covered tube allows you to mold it to fit the contours of your body, and a threaded weight that screws into the end of the shaft counterbalance the instrument.
At first, it can seem a bit unstable, but a few minutes of working with it (and allowing yourself to trust that the system works), and you'll realize that the counterbalance *will* hold the instrument up for you. You can still use the chinrest, if you want an extra feeling of stability, but if the action of holding the instrument up with your chin and neck is painful or uncomfortable for you, the counterbalance alone will do the job. Great for players suffering from range -of-motion injuries to the neck or shoulder.