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.
I love the colors in this room, especially that shade of blue on the walls! Plus, this is a good idea for a guest room set up - rather than one larger bed, two smaller ones so guests don't have to share a bed if they don't want to.