I remember rolling my own authentication system using an iButton back in college. I had it mounted on a key fob. Worked pretty well, you touched it to the reader and typed in a 4 digit PIN.
Don't really understand why these didn't take off vs. a smart card for authentication: as far as I know they're more durable and they're pretty cheap.
My favorite petition came right after a few of the early responses, titled "We demand a vapid, condescending, meaningless, politically safe response to this petition."