After the previous challenge of finding suitable plastic sheets, I finally stumbled upon a local manufacturer who could assist me not only with the material, but also CNC-mill the parts at a reasonable price which saves me a lot of time.
That means the very last parts are soon in stock. What intense months it has been.. I can hardly believe that its finally done. There's even some time to tweak the firmware and check a few extra times to make sure that there arent any bugs before I open up shop. Because when it's shipped it's out of my hands and any critical errors means I have to send the customer a new board.