I love the bookmooch painting by Andrice Arp (on the main page). Would it be possible to sell bookmarks and business cards directly, and to also sell notecards, postcards, bookcovers, stickers, shirts, notepads, etc? I'm would probably not buy anything personally, but its an awesome picture, and that alone could probably sell stuff. Not sure if whatever license/contract allows this, as the painting doesn't appear on her website (http://www.hi-horse.com/aa/portfolio.html).

http://shop.cafepress.com/bookmooch

There's a bunch of things like T-shirts, baseball caps, totes etc. there but I agree some kind integrated store here (or at least a link to that one) would probably sell better, not least because people might know of its existence.