Italian furniture manufacturer Dielle, has created what they call a ‘Container Bed’, which is a normal bed that has been raised to include storage underneath. It’s a solution designed for small apartments that often don’t have enough storage space.
Attic Bedroom Closet Design, Pictures, Remodel, Decor and Ideas - page 9 - sublime-decor. I have the perfect wall (with attic behind it) to do this. I've often thought of making an easily accessible closet there.