Bruce,
If you haven't already, I strongly urge you to contact the squad in Virginia directly. They just might have (a) the switch box, (b) photos of the car when it was in service, and (c) other misc. goodies that came out of (or off of) the car.
My 1975 Lifeliner was removed from service in Mendham Twp. (NJ) in 1985 and left the area almost immediately. Over 20 years later, when I contacted Mendham Twp. after purchasing the car, I was put in touch with the gentleman who not only founded the squad, but who custom-spec'd and ordered my car brand new! We had several lengthy discussions by phone and mail; he was just as excited that I was preserving their old rig as I was to actually be talking to him about it. He sent me all kinds of things that he still had for my car, including the original interior cabinet designs that he drafted and sent to Miller-Meteor, as well as Miller-Meteor's drafts sent back to him for approval. Among the three large boxes of equipment they still had from this car were two embroidered wool cot blankets (photo of one is attached.) I was like a little kid on Christmas morning when those packages arrived!
The moral to this long ramble is that you never know what the squads might still have, even after all these years. This is why I spend a lot of time doing thorough history searches on all of my cars.