Perhaps it is the book lover in me or maybe I love mashups that work — anyhow — kudos to Twelve South for their BookBook for the iPhone 4/4S. A vintage-style leather case for your favorite smartphone and a wallet for everything else you need a wallet for. It retails for $59.99 but I’ve seen it for $55.52 on Amazon. There is also a BookBook for the iPad/iPad2 and the MacBook Air.