A universal, federated payment protocol
ripple.com
ripple.com
Beside the tongue-in-cheek comment, payment systems are already decentralized. You can send money to anyone just by knowing their IBAN number, independently of the bank you're affiliated to.
How will your system cope with the augmentation of transactions? I see you use a consensus based system like Bitcoin, and these tend to take more and more time to converge when the number of transactions gets bigger.