Depending on your budget and what's available in your area, Lexan should be an option. That's what we use on my racecar. You can cut it with a jigsaw and bend it with a propane torch (in a very well-ventilated area).
We got our source sheet from TAP Plastics, which has a dealer in my area, but I imagine there have to be a bunch of different sources in different states. Visually clear and shatter-proof at the right thickness. I imagine it might yellow over time, but so far, so good.
http://www.tapplastics.com/