Paper wallets make the most sense to me. It's a low-tech solution to a high-tech problem. Just have a stack of paper, each of which contains the private key of a wallet with 0.1 BTC or whatever. You can make copies, and you can give them to people as payment with whom you have mutual trust. When you want to transfer some money, just scan the private key with your phone, beep boop, it's transferred.