On the University of New Mexico campus, they have bike lockers you can rent (for a semester, iirc.) They are sort of wedge shaped. It SEEMS like they are made of rubbermaid plastic and metal, but may be all metal. Anyway, they are modular, and several of them can be connected into a round sort of... thing. Nothing I would leave a bike in overnight, but for commuters with pricey parts on their rides, I can see it.