Anthropologie (kindly pointed out to me by my friend and fellow librarian, Lindsey). The appropriately named "Bookbinder Heel" itself actually looks like the spine of a book, happily resting on a shelf. This, clearly, is more than enough to set my little librarian heart a-swooning.
These beauties have officially made it onto my must-buy list. Piggy bank? Prepare to be raided.