I considered a bike rack to mean storage. But I guess someone could still slash my tires or steal my saddle...

This might be a tough business sell, because it would have to be cheaper, smaller, and much more numerous than health clubs. (which have showers & lockers)

I think maybe a better business opportunity would be to offer cyclist-specific body wipes. They would be thicker than baby wipes, about the size of a washcloth, and not too expensive.