I've thought about doing something like this myself with a Benno CD/DVD shelf. I think I worked out that it would fit in the space I have, but the books I want to store in it were about a centimeter too tall. I could put them on their side, I suppose, but I don't really want to do it that way.
So for me, it's "back to the drawing board" for my never-ending need for more book storage.
Speaking of book storage, I recently found a very interesting book on that very subject. It is 'Books Make a Home' by Damian Thompson
There are some really interesting ideas in this book. And two quotes that I love.
"When I have a little money I buy books. And if any is left, I buy food and clothing." - Erasmus
"I would be most content if my children grew up to be the kind of people who think decorating consists mostly of building enough bookcases." - Anna Quindlen