I totally want to do this: probably to hide my bedroom door. Perhaps it would make a great thief deterrent.
I need storage space under my basement stairs. After seeing this idea I thought maybe I could use some bookshelves turned sideways and tops cut to fit under stairs. Add wheels and some drawer pulls. Even thought of putting a desk that pulls out sideways under the lower part of the stairs. This could become a hide-away craft/sewing area that I don't have space for anywhere else in our small home.
Under Stair Shelving Storage Solutions ~ http://lanewstalk.com/smart-decoration-with-under-stair-storage/
Under-Stair Storage — Miles Enterprises | Fine Custom Cabinetry in Baltimore MD and Washington DC