The Nano at least is not fingerprint-based; it's simply a capacitance thing - any conductive thing touching it, connected to you, will be treated as a touch. I have at least one coworker who strung paperclips from their Nano to someplace convenient, and they just touch the paperclip.
As well, I just performed a test by rubbing my nose on my Nano, and it worked as intended :)
I'm pretty sure the nano just needs a poke and then it'll spit out whatever you've configured it to do. I got one and used it for a little while to unlock my computer, by just having it spit out a static password on touch. The issue with this of course is that your password is now visible in clear text just by placing the key in a USB port, opening up a text input, and then touching the key. It was convenient, but very insecure obviously. Maybe it would be useful to you though.
In fact how about this, you can have mine – for free. I never use it anymore, and if there's a chance it'll help you I'm happy to just send it your way. It's just collecting dust at this point anyway.
But yes, that would be one solution and great minds think alike. :-)