[aerohead]

I'm pretty sure that tooling for glass must be metal with a class-1 finish. Windshield tooling alone for the Lola GTP car was $29,000.
You can imagine an entire roof.
You'd want to do a gold vapor deposition surface to control solar insolation,like NASA space helmets.
A company in California can do it for you.Metal Crafters is the company I believe.They do all-metal concept cars and have their own ovens for producing compound-curve laminated safety glass.