Right, which is why this idea is not that far fetched because the factory essentially did the same thing twice before with the same platform.
So back to the conversion - maybe the 3rd gen. Charger doors would actually work. Presumably that's at least where you'd start since the length, height, shape, glass and body lines might already be in the ballpark.
It's likely easier said than done but besides moving the B pillar, could his whole operation be as simple as putting Charger doors on a Coronet?