Hi Greg. it's an interesting idea and I'd keep thinking about it. For temps, they are either set up in HR with employee numbers, or get separate "temp.last.first" or similar IDs.
In addition, I'm actually a big fan of using employee number for AD account naming as well

Not only does it solve the renaming of accounts when names change, it allows AD accounts to all be set up with similar (lower) privileges and forces IT users to use separate higher-privileged accounts only when needed, i.e. they have to logout of their "employee" user, and login as a separate admin-enabled AD account to do a specific task (yes, they have to have two accounts, but look at the security benefit).
Just don't do what one client I worked with did, and use SSN as employee number

and then use employee number as their login
