there is a pre built motion platform out there I beleive sold by fright props. I think it uses air bags. I know that the air bag are available on there own. there is also a device out there can be mounted to a wall for vibration. most any vibration that is included on an audio track this device is like the driver from a subwoofer but just the magnet and coil mounted directly to what you want to vibrate. I think that may have also been fright props that I saw that on.