Along the same lines, I'm fairly sure that the NSA had a RFQ out for much the same kind of thing. (Key management on PCMCIA memory cards.)

The card already exists. It is called the TESERA (sp?) card. Guess what, it uses the Capstone chip (clipper + key exchange). I have also heard a rumour that there is a proposal to use a similar version of Capstone for the Administrations Health ID card. Clipper, coming to a health care provider near you...