Would it not be possible to make that option accessible to the customer with a message that says: Do you have an account with Vibanko, Instawallet, MtGox, Tradehill (insert whatever new solutions might come here)? Then the customer can choose that particular QR code and the transaction is instantaneous.
The merchant's QR-code can contain the valid options and the smartphone software can know your preferences in advance and pay with the valid option you prefer automatically.
Going back to my earlier proposal, at this point, if you don't have an account with any of the valid options, you could send them to your payment processor and he can ask a partner processor to do the payment for them. If the partner can't do the transaction neither, he can ask to other processors. In the end, payment processors will establish an effective ripple network.
The bitcoin community could gain a lot by supporting the decentralized implementation of Ripple.
Again, this green addresses idea is very promising.