Wired News: Chameleon Card Changes Stripes

This is an excellent idea. It increases security, and convenience in one fell swoop. It is also forward compatible, including open ended RFID programmability(you know those things are going to be big) and personalized biometrics. So long as the things are reliable, I'd buy one in a heartbeat. I wonder how stores will react? The concept seems to raise the specter of spoofed cards, but you'd need to steal the original card in the first place anyway, so why bother using a chameleon card?