I think that's effectively what Ripple is trying to do (https://ripple.com/ https://ripple.com/) -- a sort of Hawala-like exchange protocol with an open ledger,

I think that's effectively what Ripple is trying to do (https://ripple.com/ https://ripple.com/) -- a sort of Hawala-like exchange protocol with an open ledger, mixing in their own cryptocurrency. At least, that's the way I thought of it since I last looked..