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.
DIY: Using IKEA Shelf Unit as Storage Bench Better Homes & Gardens . when changing table goes out, this can go in. still use baskets if needed. Ikea Lack shelf unit w/ legs is good for over the heater vent.