As goofy as this sounds, you might first want to try the regular windshield companies. Many of them merely put obsolete stock into storage, rather than scrapping it out, as they take up very little space. For example, I know of a guy in the UK who needed a windshield for a Pontiac Parisienne convertible recently. Not only did a company have one in stock, he also had it fitted the same day!
I have heard similar stories over here.........worth a try !