This is the simple interface box made up of a keyboard chip connected to terminal strips in an alphanumeric matrix.
Pretty simple, cheap and effective for my use. Rough diagram below.
For the panels it was a lot easier than I first thought. I used a method Goupil used on his F16 pit at "check 6".
I drew up the panel art using Visio and sizing from the graph drawings from the beginning.
Make up the artwork, print it using a colour laser on thick sheet.
Then I cut 3mm MDF panels using a paper copy of the panel glued on and cut to shape. Pulled off the template, glued on the finished print and trimmed where necessary. Sprayed it with clear satin spray lacquer (Tamiya) and fitted the switches.
Its not perfect, probably needs a little more spray and more care on the corners.
You can back light these if you wanted to cut a small area out behind each text area on the MDF then fit a diffused light source behind. I wasn't prepared to do the extra work at that stage. Would look better though.
I have to use a light source inside to illuminate them.