If you have a printer, I can recommend self adhesive vinyl sheet. You can make your own panel with ply, thin MDF, dibond, perspex, ally sheet etc. Print your mimic diagram (I use Anyrail and PowerPoint for the artwork) onto plain paper and tape to panel. Drill everything through the paper template. Remove paper and apply vinyl in its place. Using a sharp knife cut the holes in the vinyl to match and then attach switches leds etc. I hold leds in place with a dab of superglue. I would also recommend sealing the vinyl print with spray matt lacquer first, just as you would for card buildings.