Name changes could be easily implemented. Heres a good idea. Let's steal a little bit from Half-Life (kind of).
Let people change their name all they want to, but keep their base login name the same. They login with the same login/pass all the time, but can use different nicknames. Give each account a specified ID address, like... lets say... anrkist signs up! he gets the ID. "DP0001", no matter how he changes his name or anything, he will always be affixed with the same ID "DP0001". So, in general, when you type names, it will show everyones login/nick/ip/id/ops.
[Anr;Anrkist;69.95.55.55;DP0001;0ops]
this would also make for a better banning system, so that you can ban their ID also.
Pretty much expanding the player ID function to not have their ID counted when they join the server, but always being affixed to them from logging in.