I also seem to recall certain members having other "metal" membership titles, although I'm not sure if they did that because they were staff and have the option to make custom titles where the Copper membership is displayed. I can't remember who it was, but I seem to recall a gold or platinum member title.
My original custom title was Gold Member. Mprep then one-upped me with Diamond Member, so I had to go one further and become a Lambo member.
There are some moderators and global moderators have special titles. See more:
Admin, moderators, ex-moderators (?), and very reputable users have that priviledges from theymos, who wrote it somewhere.
That one is for display name, but at least we know moderators have that priviledge.
can someone provide a good reason to change your nick without talking to an admin first no matter your status?
I can see stalker and such.. maybe personal info getting out but I cant see any need to do so without talking to an admin. And sorry but that includes all ranks, if I can become a hero member, anyone can and that scares me.

Only moderators and members who have sent 10+ BTC to the forum can change it automatically. Hero members can't.
It's just a convenience.
Welsh said but it seems incorrect.
Only VIP members (50 btc), Donators (10 btc), Global moderators, and admins can display custom titles.
See that one too:
https://bitcointalk.org/index.php?topic=4549955.msg40980684#msg40980684