It had to be 20-25 years ago I read a Kit Car magazine article about a company that made custom curved windshields for limited production (expensive) or one-off (insanely expensive) applications.
I can't find the 20-some-odd year old magazine (go figure) and can't remember the name of the company.

Has anyone remembered to take their memory pills, does anyone remember the article or the company, and are they still around?

WHL  

Not sure, but I would think that some company would be able to provide this service, even if it isn't the one from 20 years ago! Now I can't vouch for how expensive it would be and I guess it would depend on the application, does anyone have any advice or resources for this?  

I got my 300SL from Pilkington glass. I think they are in England. They manufactured a run of 50 windshields, rear glass, side and vent windows etc. for the 300SL when they became unavailable from Mercedes. I can only imagine the cost. I am told that they typically make a carbon/graphite mold. So that already sounds expensive.

You also have to decide if you want "safety glass" or "tempered glass". A more realistic approach for prototype or low volume would be using plastic such as polycarbonate or Lexan  

Yeah Lexan is a good option, you might be able to get a basic template some where though, i mean people chop glass in some cars so it can be done.