A MIDI patch bay?

I have been looking for a MIDI bay patch for years, even decades. I even studied the feasibility of such a device on several occasions. In fact, the constraints in terms of feasibility, complexity, functionality and price are really strong. 

On the strength of all my tests, I decided to tackle the task again. I am currently studying the motherboard of such a device:

This is only a first prototype but the final version should look very much like this, in much smaller ...