Granted I know the answer to this - there's no market for it BUT I would like it as a service.
The only place i can think of is in service stations. But if I wanted to go for a run at lunchtime, I'd have to stink for the rest of the day.
Only answer is to join a gym, but then you might as well use their training facilities, and I don't want to.
Me bird used to live on a boat with no heating or hot water, and she joined a gym just to have a hot shower every morning.