Hey Cal,
While I was in the Army, I saw many tents designed for working on large equiptment in the field. They resembled the quanset huts used by the Navy during WWII in the pacfic, except they were made of OD canvas, no windows, just 2 large closures, one at each end. This allowed trucks, tanks, cranes, etc to be driven straight thru. If you can find an Army post, check with the PDO, (Property Disposal Officer). You might be able to get one for pennies on the dollar, or find where another PDO is trying to dispose of some of these.
Take care!!!
Andy