I would suggest first getting the protoypes tested well and then going for the GB.
I would be more than happy to help and supply acrylic cases and anything else I can.
One thing to note however is, we should not sway completely away from the original idea of "extending" the GH60, so we don't need a new controller, extra USB, etc. And the GH60 and the GHpad can both be integrated in one case.
It goes without saying that if Regack can do some magic, and make it so that one PCB can perform both tasks, then that would be amazing. Maybe use a dipswitcch or jumpers.