[Bicycle Bob]

I just read this whole thread, and a couple of points come to mind. Vision through near-flat rear windows is bad. If it is scratched plastic, it is far worse. Polycarbonate (Lexan) scratches far easier, and is far harder to polish than plexiglas. If it is flat-wrapped, you can protect it with a layer of Mylar, which is scratch-resistant and cheap to replace, with tinting options.

Personally, I prefer the idea of a Coroplast cap that is light enough to readily hinge to one side and be quickly mounted or removed by one person.

A bit of background on possible investor reluctance: Bruce Myers invented the Dune Buggy. He got a copyright And a patent, and got busy churning them out. After two years, he caught up with the orders, and noticed that he only had 15% of the market. Others had made molds from his early work and gone into business too. So he called the lawyers in. It took a few years, but he wound up broke and divorced. Better to sell all you can, and move on when the market fills. Unfortunately, the development costs are only worth as much as the lead time they give your marketing department.