Use drawer slides; mount the drawer on the wall; attach the shell to the slides, so it pulls out. Shifty Desk / Hallway Stand by Daniel Schofield This is such a great storage idea! It can be a shelf and a drawer.
An update on my DIY Tufting Technique. I realized that I could completely bypass the whole threading-a-button-through-the-headboard-holes thing by just carefully screwing a wide-headed screw down in through the hole I had made in the foam.