I’ve been wanting to do this for a while now. Maybe its time…
How To : Vacuum Form Your Own R/C Car Body!: http://youtu.be/QuOAk0pgsGY
Absolutely interesting; I made a lot of time ago a small vacuum forming machine from wood and using polistirene picnic dishes for forming small parts for RC planes and it works, but it is too small for an RC body. I’m thinking to build a bigger one. Recently I’m try to use the old one with “master” pieces made of 3D printed PLA parts, and it works, also if you melt the polistirene to be formed on the 3D printed part, the pieces does not stick together, so you can remove the master. I’m thinking to print multiple parts and mount together to made a master for a touring http://youtu.be/QuOAk0pgsGY?t=1m10s car body 
what do you think?
I would like to make one too, but using some other heating element than an oven, perhaps a cheap ‘3 bar fire’ or the element from one of those halogen ovens.
I think 3D printing the body in sections and then vacuum forming it should indeed work pretty well.
Mind you, the ‘bodies’ ive seen for some buggies/truggys are so small you could easily fit them in 180x180 - its the touring car and truck bodies that are pretty large!
It’s also on my long term to-do list. I tried printing a medium complex body nearly a year ago, and all the slicers I used crashed big time on it. Would be great if OpenRC had it’s own body.
Building up a master from multiple printed pieces will work fine. Make sure you sand your seams to get the best result. Also a vapor dip of the master can help depending on the thickness of the plastic you are forming (the thicker the plastic the less the fine detail). Also, using a kitchen oven to heat the plastic works great. Many will lock the plastic sheet in a frame, heat the plastic, pull from the oven, have the vacuum on, and immediately form over the master.
His video is spot on for method.
That’s fairly cool. I didn’t catch what temperature you said you set the oven to. That would have been good to repeat their towards the end when you were in the kitchen. Also might have been nice to mention a bit more detail of how you constructed each of the boxes. But the safety first dialog was appropriate. And the Intellectual Property and Fair Use was good to hear also. Thanks for sharing.