I've got a tangent to go off on here.
I read a newspaper article about this company a year or two ago, and comments of the OP made me think of it right away.
http://www.driveatank.com/
This is a business run by a collector. There were postings for 'tanks for sale' even!
This all happens about 90 minutes south of Minneapolis, MN.
Back to the topic though, it's a great point. There's quite a few armored vehicles out there if you know where to look.