Do a google search on GCR415, and you will find there already is software out there for it (assuming you run Linux). I'm not sure if it will work with Windows natively or not, but it might. As soon as I get a chance, I'm planning on compiling the driver, and giving it a go for storing SSH keys. It's totally ridiculous, as I doubt anyone is interested is swiping my server, but it should be a fun project.
BTW - there seems to be a couple of standards for "smart cards", so you should be able to find compatable, blank cards. Ironically, one of the standards looks just like a credit card... ;)