I would be in for a prototype too if you don't need a 100% guarantee that I will manage to solder it properly!
I have switches, a cable, soldering stuff, no experience and balls!
I have no case to test it with, but I could at least make sure I can solder switches and plug it in! A poker plate would help too else I will need to work on desoldering skill a lot after!
So all in all, I would like a prototype if you need a number to finance them, but I am not the best candidate to really test it!