This is the climber prototype built by Team 449, the Blair Robot Project. We weren't sure how legal it was to use Velcro, so we build what I've been calling macro-Velcro: spinning "hooks" (actually just bolts) that grab a loop. There's also a slipknot that allows the rope to wrap around the winch reel a couple times before it starts bearing a load. We complete the climb in about 6 seconds. Questions/suggestions are welcome!
Video
CAD:
