Xponder

 

 
The 7-segment LCD displays I use are green. By putting purple colored translucent plastic film between the displays and the rear side of the transparent acrylic glass panel, I achieved yellow displays that look very cool (and not like they were ripped out of a first generation electronic calculator).

The grey connector marked "xponder" is wired to the 4 displays. A flat ribbon cable from the EPIC 7-seg. display module is inserted here .

The cables from all the switches are connected to another ribbon cable that plugs into the autopilot panels (thus saving one strand of cables to the distribution module).

Close-up of the test push button. Instead of using a flat nut for connection of the button to the front panel, I used two threaded M2 rods to hold the button in place. It is important to get the position of the white cap of the button right before using glue, else the button might get stuck when pressed.

The result is a much more clean-looking front panel.
Close-up of the 7-segment displays. Using individual displays gives ultimate freedom of choice regarding size and color, but manufacturing is difficult. There are many soldering points in a very small area, so patience and precision are required.