I think another issue with an American ZTL is the exact reason why ZTL cancelled their plans to expand to cover American collections: some major American zoos are very overprotective over their species list and have threatened legal actions (however weak) against sites publicly posting stocklists. This is also the main reason ZIMS is now private as far as I've heard. Even then, several zoos have refused to join ZIMS for the sake of keeping their stocklists a mystery for some reason.
~Thylo
~Thylo