Mark Kinsley, a product designer, developed space-saving fold-down shelves known as Riveli Shelving. Not only do they fold up and down in many configurations, but you can customize them by creating your own design on the front of the panels. So basically artwork that turns into shelves.
You can find Riveli Shelving at Iconic Revolution.
Kinsley is currently in search of a manufacturer who will help him create a drop-in panel system so that you can change out the panel designs too!