Oooo, Maxfax your talking my language, LOL!
I have a 99 GMC Suburban 1500 and might try looking for one for that or 98 year. If it is this simple, I want to try to make it work. I would be interested in the wiring diagram for this year; then go and see if I can find one. Is true that one would have to change the mirror mount, but that shouldn't be too bad.
Oh, I like your idea of the mirror with map lights also. We have a 2004 Impala which has 2 map lights on it. I wonder if one could find an Imala mirror with the map lights, compass and temp (LS models?). That would be a cool upgrade.
I have also thought about mounting a light/sunglass dome from another vehicle that mounts near the sunvisors since VW's mk1, skimpy light is always falling down, and doesn't give much light anyway.
I wish Ford had some temps/compas lights also, much like you found. Cool find you had. It got me thinking!
I love to hunt at the junk yards too!

Thanks