Agreed. While the ideal solution to this problem might be server side, as the author suggestions, that is in no way a feasible solution. The card networks are

Agreed. While the ideal solution to this problem might be server side, as the author suggestions, that is in no way a feasible solution. The card networks are in direct competition with each other, so there's no way you could get a single card with Visa and Amex/MC on it, not to mention there's competition between issuers. Heck, I can't even get my Chase credit account and checking account on the same physical card and those two are tied to the same user account at a single bank and go through a single credit card network. I can't wait to get my Coin. I'll probably still carry around the Coin and a backup card, but that takes me down from 4 to 2.