Multiple passwords on a user account

I would like to implement this for my user account on my server. I am thinking that the primary usage will be on untrusted public terminals in a library, lab, or even someone else's computer, which may have keylogging software on it. In this case the typed-in password will be valid for about 10 seconds and then never be useful again. However, I do not want to *require* the usage of this, because it would mean digging out my PDA every time I want to authenticate with my server. Does anyone know if it's possible to configure PAM to accept multiple methods of log in on the same user account? I.e. if it's my regular, static password, let me in, but also let me in if I typed in a valid OTP token as my password.