Well the wheel never stops turning. I raised the same question a long time ago.Most said it was not possible, but Colin thought it could be done. Well been stubborn Irish I did buy slide glass on EBay & I also used the glass from photographic slides from my days doing slide shows, they were made in the USA by a company named WESS slide mounts. After a bit of trial & error I found I could cut it easy & grind the edges as well with the diamond wheel of a Dremel. How did I do it, well I carefully clamped the glass on to a piece of plywood fixed on my bench with an overhang(please wear goggles because you will break some(not as many as you would think if you are careful) Don't squeeze the clamp too tight & make sure that it is spotless clean under the glass, otherwise you will crack it( after you crack a few you will learn quick)You can with care even do curves. I was working on a rig to hold the glass better but I got very sick. I had done nearly all the windows of my Smit Nederland at that time. The breakage got less & less with practice & by taking my time. I wish I knew how to put some photos on here but that I have not mastered yet. When in place you can clean them with glass cleaner & a Q tip.Colin is right the glass looks much better than plastic. You can also glue the glass pieces together edge to edge with epoxy & it is hard to see if you need a bigger piece than the slide glass is. So have a go , you will be happy you did. Mick B.