plastic source?
 

Does anyone know where to buy sheets of OEM type plastic? I guess about 1/8th - 1/4" thick... just the type of plastic used on the Alero bumper covers/rocker panel moldings. What kind of plastic is it? ABS? Would window repair shops that sell and cut acrylic panels carry or be able to order this stuff? I could use acrylic but it is very expensive when its thick and also very brittle and hard for what I need. I love being able to cut the plastic with tin snips instead of a demel cutoff wheel with acrylic.

the plastic used is either TPO OR TPE SOME OF THEM I HAVE SEEN USED PP
OR TEO
you could get a junk yard bumper that is the same type of plastic, to aide in your quest

Good answer... but make sure if you use pp its copolymerized with at least ethylene or else your properties are going to be shit
How many sheets do you need... and how big?

Actually I decided to go with "puckboard", its the stuff they use to line the inside of a hockey rink. It is known for being indestructible. Unfortunately you can't glue, sand, or paint it, but some vinyl wrap should cover it up. It is only available in white. It is high-density polyethylene (HDPE) whatever the hell that means.