Yet another not-answering-your-perl-question, but you may be intersted totally ripping the guts out of your existing infrastructure, and changing the uid -> user mappings to be done using LDAP or Yellow Pages/NIS instead of bundles of /etc/passwds.

Ofcourse, you may have already thought of a centralised directory and thrown the idea out because you're on many sites, don't have that many common users accross all boxes, machines run vastly different OS's, your boss won't pay you to do it, etc too

But I did the LDAP thing once, and it was neat, slap in an export of /home, and some ssh keys, and you're away laughing. The place I'm at now uses NIS, and exported homes, but same deal.