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.
designed by Sylwia Ulicka Rivera. Made from rubber treated to be very elastic and spongy this unusual piece weighs less than 3 kgs and juts out only from the wall. A flexible drainpipe starts above the central point of the tub making it easy to fold up.