Without knowing any better, and never having seen one like it before, I'd hazard someone fabricated it as a one-off.
Agreed, but it does look an awful lot like a factory hard top from the 70's. I wonder if it started life as a factory top?IMHO, much too well thought out and well crafted for a one off. I too, have never seen anything like this, but very cool. Might have been one of those great ideas that was marketed at too high a price for the market and discontinued. Have you asked the owner where he got it from? It's history would be very interesting, good luck Allan