On the construction of the vacuum system, this site has great info. http://www.joewoodworker.com/veneering/ ... mpress.htm
This guy does vacuum clamping for veneering, but has jigs and plans for vacuum hold down and other uses as well. He has one design where you pump up the pressure and flip the valve to pull down whatever you are working on, and the pump only operates to compensate for leakage, to me that seems like a great option for thermo-forming, as you can have a strong pulling force all at once.
Axman has had one of the vacuum pumps he uses in some of his plans in the past.
Also, material wise for the pedal powered (whatever it will be). There's a guy (Cliff I believe) who has a lot of alumabond and similar materials he wants to sell. I have a bunch of pieces under my CNC you can check out. It's basically a sandwich of thin AL 1/4" or so HDPE and thin AL. It's used for structural and decrative stuff. It can be bent in a brake, or by hand into any shape, it holds it's form, and it's much lighter than a solid AL panel would be, and cheaper too. (but it's still not cheap). At any rate it would be nice material for the pedal thing as it's light, but can hold it's shape on it's own.
Dibond is another variety the guy has some of.
I wish I had more time, but I'm going to focus on the CNC so it can cut mold's etc for the pedal project.