Interesting. My initial thoughts were around a business built on that (better so...

Interesting. My initial thoughts were around a business built on that (better solving the problem I'm trying to address), but just an API could be huge.

Looking around the internet, I've found a couple related things:

Google Wallet creates a "Virtual OneTime Card" underwritten by The Bancorp Bank for each transaction. https://developers.google.com/commerce/wallet/online/faq

Citibank lets you log into your account and create a "virtual account number." http://blog.credit.com/2011/06/worried-about-online-security...

This (brief) thread in a MasterCard forum, referencing closed APIs. https://developer.mastercard.com/portal/display/forums/One-t...