Chameleon Networks has started taking orders for, Pocket Vault, a new device that holds all your credit card information and reprints it on demand to a reusable Chameleon Card. All you do is select the credit card you want to use and it spits out the Chameleon Card with the appropriate imprint and magnetic strip. The Pocket Vault includes a fingerprint reader so that only you can use it, and also supports data back up to your pc. It also supports RFID, the electronic tags used in gas station speed passes, office building key cards, and electronic tool booths. Pocket Vault is a bit big at the moment, but I'm sure the size will come down.
$179 on Chameleon Network's Site