Very cool! Already been scheming with a friend of mine on a good experimental procedure and documentation method for testing the different methods of joining. I'm going to order up another ten feet of belting, I think, so I have enough to get some repetition into my testing and some statistical accuracy.
As far as I can tell, this really breaks down into two categories, removable, and non-removable.
On the removable side, we have (non-adhesive) shrink tubes, zip ties, tapes, folding etc.
On the non-removable we have adhesives (including adhesive shrink tubes), mechanical fasteners (staples, wire stitching, etc), and crimp-type joins.
Once I have my X-Carve set up, I'd like to further examine how much fastening is actually required. Sure, a piece of thick-wall adhesive shrink tube will stop that belt from ever slipping... but would a simple zip tie do just as well in actual use? All kinds of fun ideas here! I love experimenting.