Adding Biometric Security to an Existing Laptop?

008 asks: "My work requires me to travel to some harsh climes with my laptop and other equipment, and the data I collect there is potentially very sensitive. Currently I use the PGP family to secure my drives, but my paranoia always demands more. IBM's biometric-ready Thinkpad really piques my interest, but getting one isn't feasible for me because it's too wimpy for the physical stress I'd inflict on it. I'd much prefer a way to biometrically lock a computer I already have. What options are out there?"