OK, all the machines seem to be functional. However, on several machines the admin profile is corrupted and when you log in as admininstrator you get a new profile based on "Default User" and it's called something like "administrator.Lab-B-02". This is similar to what happens when a machine's power is pulled while someone is logged in. The profile is not released and when they log back in a new profile is created and named "<username>.<machinename>".
Discussed this with Martin. His suggestion is to rebuild a handfull of machines and try rebooting them before logging in to see if it just needs another boot cycle to release the profile. It's easy to try and just might work, so I'll try this sometime, just not right away.
This morning I checked the machines I left ghosting last night and 13 were fine, profile-wise, but 9 were flaky. Two weren't entered in to the domain for some reason. I also rebuilt all of Lab C without renaming them or putting them in to the domain in order to test a theory regarding the profile problem. It had no effect other than making me manually rename and enter each machine in to the domain. About 12 machine had flaky admin profiles, and 8 were perfectly fine.