How about trying to sell ads directly to booksellers? Even if affiliate programs won't work, you could offer users up the same kind of book list as sort of a customized banner ad. Being able to serve up that many impressions must be worth something, even if only for a short time. Even sites that don't directly sell books, but are related (back to goodreads, because its the only one I have really used) would probably be interested in this. Hope you get something off the ground.