I have found some older ones for trucks on Craigslist and am trying to purchase them to try to make it, never seen it but love it on the older cars!!I think this would look awesome on a 4-Door. Maybe you can cut one out of cardboard and take the piece to a medal fab shop. As far as the hinges you are probably going to remove your headliner to anchor this.
Please let us ( me) know how it goes as I would like to copy your success for my Missouri More Door.