There is a similar competition/show in Texas? I think GAMES magazine had a
brief article about something like that within the past 2 years. Also a
children's magazine (I think 3-2-1 Contact - but I'm not sure) had an article
about a college art class - each student had a junk car (was it a Yugo?) to
transform. It had some pictures with it. Those are just other resources.
As for materials - what if everything had to come from the car itself?