The initial question was, "Who is God, & why does he know so many Zeds?" What I really want to know is, why are all the single character usernames taken by one user named Zed!
The question is meant rather serious, yet tounge in cheek.
http://pownce.com/god/ has 20 friends, two of which are not "zed g". He also looks a lot like Mr T, but I'm sure that's another story.
I think it would help you guys and your users to have more descriptive error messages in your forms. For one I just did a little test signing up for a new account using a known duplicate user name, and all it does is take me to the Ack! page. I'm sure a lot of people are ending up here when creating a new account. In that case a simple, "That user name is already taken." would suffice.