http://www.amazon.com/Kryptonite-Sta...ies/B000BS0D4Y
Or do you need a gigantic one like you got? If so, I'd get a Krypto chain.
http://www.amazon.com/Kryptonite-Bic.../dp/B001KQ5ZRG
As far as the other keys opening it, that's tough to do with better cyclindrical locks because each groove is cut to a certain depth. I've had a cheap lock that only had 4 cuts and 2 different depths so that's only what 4^2 possibilities? 16 different keys. Old Krypto locks had more different keys than that.
I never could get the pen thing to work, but I only tried for a couple of minutes.