The dash controls are a Chrysler product from the late 70s through I believe the early 90s used in their vans, pickups and possibly mini-vans. I spent several weeks checking out salvage yards a few years ago and came away with several and I think I paid an average of about $25 for them.
They also show up on ebay from time to time.
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)