Today I've built my first paper car from the amazing collection at Inkjet, Paper, Scissor, a papercraft blog run by Grendels_Mother64 also of the Cardboard Warriors forum. This model was printed at 50% scale to make it compatible with 15mm minis. Even at this reduced size it was very easy to build and looks great.
My advice when building them: glue one side to the top, then the other side and finally the floor. Now I have to build a few more to use in my modern games. Come to think of it, I now probably have more than enough terrain to play All Things Zombie.