The Vectrex 3D Imager, the proto-VR headset for the Vectrex --essentially an elaborate set of stereoscopic glasses-- is a lovely, exotic, and usually expensive accessory for the vector based console, and one you can bid on via this Vectrex 3D Imager eBay auction. The headset comes in its original box, has been tested and is working, and comes complete with the 3D Minestorm game, but lacks the colour wheel.
What's more, a complete, boxed copy of the 3D Crazy Coaster is also included with this Vectrex 3D Imager. My sources, the only person I know to have actually played this thing that is, tell me it's a pretty impressive piece of software too.
Seller ships to most places worldwide.