Good one Steve, yes I have heard old plastic milk bottles cut up. Even tongues of old leather shoes will do a neat job and look cool. As for the rivets. From my Balloon Bicycle collecting days, there are available threaded studs that look just like a fender rivet on top but have a threaded end with nuts to install conventionally instead of with a special rivet tool. If anyone is interested in a source, let me know as I believe I can still find them.
Ray Homiski
Elizabeth, NJ