The printer I use with the 3D Chameleon is way up high on a shelf. I created some simple stepper motor rotators so I can see when filament is being driven in/out and also what filament is being unloaded and loaded. There is an oversize gear for the extruder and a windmill for the selector (sorry I didn't have that exactly aligned for this video, needed 3 hands! but you get the idea).
Video of it in action:
I used a pressure-fit 8x3mm neodymium magnets I ordered on ebay:
Ok... those are cool!!! Thanks for sharing!