I've seen this kind of DIY work well. Since a lot of parts are getting harder to find, this might be a way to knock off a few spares from one good part. Like taillight lenses? Or safety belt covers that always break up? http://www.vacuumformerplans.blogspot.com/ Even a manual vacuum pump DIY: http://www.instructables.com/id/make-a-manual-vacuum-pump-for-under-%2420-by-convert/
When I was a teen, I got a summer job with a bumper stamping company that made and often designed new bumpers for GM, Ford and Mopar. They made the mockups out of laminated mahogany lumber, for the female and male dies, and then pressed a couple for the engineers to test on prototype cars. To make a thermoplastic mold, you'd only need a lightweight male part and the vacuum pump and heat would do the rest. So, if you wanted to build a custom roof console, you'd make up the shape and the mounting brackets from say a chunk of lightweight balsa wood, test it out, then borrow the wife's oven, while she's out shopping . OR, you could make up a solar parabolic cooker on the patio with an old patio umbrella and aluminum foil (like India has for 5,000 years) and a glass aquarium with the pump attached for bigger peices. The work is in the model. Since most of the thermoformed plastics take shape below 250F anyway, there's not much chance of flaming out. You can even embed the fasteners. Even custom cupholders!
