It looks like I managed to redesign and print the new concept.

I kept the latest concept, and printed a few baseplates what screwed together, designed and printed a module for breadboard and BeagleBone Black (actually I used green, but doesn't matter).

Here is the first project I started to build on this platform:

This will be a keyloq style remote for my OpenHAB home automation.

The design files for the base and the modules will be uploaded shortly.