Somebody at Nomad had a pretty good idea. They've added a 2400 mAh battery to a men's wallet. So you can carry your cash, a few cards, and some juice for your phone. The device is supposed to give an iPhone a full charge. While I'm one of those minimalist-wallet freaks, I'm tempted to try one of these. You can get $20 off if you buy before November 15 with the above link.