theymos sometimes changes names for users, however, that's not happening very often, so do not get your hopes up.
You may PM them about the request, see if it leads anywhere, but honestly, I think that's wasted effort.
Moderators and VIP members can change their names on their own, but I doubt it will be worth the 50BTC you'd have to pay to become one to you.
If you want another name, start off from scratch. Either that or stick with what you picked while registering. Those are your best options, I'd say.
Correction: All donators can change their username. However VIP members can also pick a custom title. Nowhere it's stated that only VIP's can change their username:
If you donate 10 BTC, you can get a special "Donator" title and a green "who's online" color. If you donate 50 BTC, you get VIP status and the ability to create a custom title for yourself.