This is one for all you model railroad fans. My husband takes and makes his own structures (businesses, houses, etc.) out of cardboard. He saves tons of money that way. If you look at the catalogs for buying model railroad structures, they can run into pretty big bucks. He just designs his own out of cardboard and sometimes toilet paper rolls. Cheap, but they look fine once he has painted and added windows, doors, and other things to them.
I would love to see photos!
check out www.papertoys.com
There are lots of models you can print out. Not sure if the scale is right; but you can probably use a photocopy machine to enlarge them or make them smaller.