The grounding patch is finished. It has two strips of velcro hook sewed on each end of the stretchy conductive fabric. I secured one side with the velcro, then gave it a stretch over to the other side and tacked the other side down as to make a nice smooth addition to the top. A wire is connected by crimping force under a metal gromet to connect the fabric to the Teensy board. In addition to providing a grounding patch, this is where I anticipate most of the wear to be happening, so it can be replaced at a later date without having to replace the whole hand support.
What is left? Well, all parts are done and working. I need to design and mill a new bottom cap on the track ball module as the current one is a little too short. Once that is done, I'm guessing it is time to start making some silicone molds of these CNC machined parts to be ready to reproduce them and make anther full trackball to prove it can be done. Once they are reproducable, I'm thinking I'll need to get a few in the hands of alpha and beta testers to see what needs adjusting.