I work in an industrial area with big rectangular buildings all over (bicycle factory, fish processing, school bus storage, the town dump, etc) but unfortunately the ground sucks, it's old asphalt that was probably put down 20 years ago.
However, there is a big unfinished concrete building that nobody cares about. It's just a shell, but the roof is finished and the ground is perfect (but a bit dusty/dirty) concrete. I've been sweeping it out prepping for the rainy season. I'll try it out when most people are taking their holiday break next week to see if anyone bothers me or calls the cops. It could be a lifesaver this winter. If nobody gives me any trouble I might push my luck and ask the metal fabricator in our zone to build a little flat bar to keep in there.