Indoor Dog Run / Park ?

I am in a small town where a lot of apartment dwellers have dogs and there is no dog park here. I am at the beginning stages of putting together an indoor dog run but I am having trouble finding examples. I like the idea of having no mud, no wind and being able to go after dark (which will soon start at 4:30pm).

I have warehouse space available and I think something the size 2 tennis courts would be about right. But I want to see what other facilities have used for floor covering (needs to be soft yet cleanable and not too expensive).

Any examples or ideas appreciated.