I made a small case here to install the RGBi converter board from http://www.bit-c128.com together with a Gonbes GB-8200.
Everything is just plugged together. No screws are needed.
The case consists of 3 parts. The bottom, in which the two boards simply have to be plugged in, the upper part and the feet. The upper part already contains the control buttons.
No support may be applied to the upper part. Otherwise, support is also printed inside the control buttons, but cannot be removed. And the buttons are then fixed.