Had this idea the other day.  I think it is pretty neat.  It is meant for the big size bookstores and it would probably work in getting more people to visit the stores.  How about having a book library service within a book store.  A small section of the bookstore could be turned into a library where people could borrow a wide selection of books for let's say up to one month at a time.  Of course, these would not include the latest releases.  By being in the bookstore, these "book borrowers" would probably also be tempted to buy some other books, or at least get a cup of coffee while there.