Just throwing things out there (and I cannot remember if you are using SP2 or not)... Sounds like someone has an outstanding case on it.
One thing I had was my user table was getting poop in it because of a check box. The AD field was screwed up (at one time) and then it moved from that field to the first name field (where it prefixed our domain name)
I think it was Convert Native Users to Active Directory User was checked off and some of my fields were done akwardly with the update. I think they fixed this in a roll up.