1953 - 1956 Corvette: http://www.corvettepacifica.com/products/4974/mirror-interior-rear-view-diecast-reproduction-53-56/ I read that late 40's early 50's Studebakers have this setup too.
John, Many euro-cars had dash mounted mirrors and I am sure that they got used. I believe that there was also a later '50s or maybe 'early '60s MOPAR with a dash mounted mirror. I can see the dash in my head but can't give you the car that goes with it.
Looks like the easiest setup for me to find as a new reproduction is the Corvette stuff, 53-57. Looks like the bracket/stand for the Hardtop and Corvette might be the same?
They're not that unusual prior to around 1955. Go leafing through some books of cars from the '40s and '50s and you'll see plenty. '53-54 Chevy hardtop is probably the easiest to find. It's what I plan to run in my '51 Chevy coupe when it's, you know, no longer in 10,000 pieces in my garage and can actually move under its own power.
I've never seen them together, but I wouldn't be surprised if they are the same piece because GM was an absolute master at using the same exact part on different cars and there are other passenger car parts that were also used on Corvettes. I sold my low-miles '53 Chevy steering box to a Corvette restorer - the entire front suspension is the same. Often the prices are lower for "Chevy" parts than "Corvette" parts on auction sites and from vendors, too, even when it's the same part. You can actually make money buying "Chevy" parts on eBay and reselling them as "Corvette" parts!
John, you mentioned early '50s Studes may. My '50 Champion is mounted from the split in the windshield. However, Starlight coupes and Convertibles where on the dash.
Triumph TR-3 mounts to the dash. Small black wrinkle finish about $30.00 http://trf.zeni.net/TR2-TR3Handbook/30.php
My 51 Studebaker Champion had a dash mounted rear view mirror. We reinstalled it after the car was done but I could no longer see out the back window because the car was on a rake ..... After giving it much thought, I made a new bracket from a piece of aluminum I-beam and polished it when it was done. I'm not sure if you'd call it a billet piece but if you're trying to stay traditional (whatever the definition of that word is), you could make it out of steel and paint or chrome it.
We used to flip the center windshield molding on '49-'51 Fords. That positioned the mirror at the bottom (just off the dash.).
My wife had a '61 Dodge when we got married and it had a huge dash mirror with a swivel on each end of the stalk.