I used to know a guy in Orange Park, Florida that cut a hole in one and installed a 7000 BTU window unit air conditioner. He also wired it for interior lighting. It was a great out-building. His was painted brown and placed in amongst some pine trees. Nobody cared.

 

They aren't air-tight, but could be made that way with a bit of welding. If you live near a port they're fairly cheap, but getting them off the truck still requires a crane.

 

Maybe have it elevated a foot or so.....

My wife's Aunt had a trailer (from a tractor/trailer) in their back yard. They had the space for it so it was out of the way and far from the house. It was painted green and masked with pine trees. Very inconspicuous. They had a set of steps going up to it. This thing was huge inside.

 

Just a question here: Since they are made of metal, would the sides transfer the heat or cold of the outside temp, and make condensation on the inside?
I've loaded some, but they were up on trailers. Don't really remember if the insides were wet or not.
If the container was at ground level, would they have more of a chance to get condensation?
Jon

Edit add: see post directly above this one. Seems like a little air under it would help a lot.

 

a freind of mine has one on his property. he stores his harley in it among other things.
as mentioned, it usually seems kinda damp in there.

another thing to keep in mind is the potential for having to jockey stuff around to get something behind it out - as they are long & somewhat narrow.