We love this great idea of adding storage yet using up no floor space. If you've got room in your walls, you might consider doing something similar to this awesome project we spotted over at IKEA Hackers.
IKEA Stuva cabinets were inset into the wall and then framed out in molding to give it a built-in look. The result is ample storage as a night stand and shelving in a small bedroom. Of course, this type of project requires a bit more carpentry know-how than other projects but the space-saving aspect is worth it. For detailed instructions on how to do something similar, run over to IKEA Hackers.
(Images: Mac Flores/IKEA Hackers)