Ah, yeah I was sure I was reading about it last year but wasn't sure if it was a functional service
Btw I don't think there is a legit reason to implement this. It's 2018 and most people should already know which char do they want to play (like there is not that much of a choices on IL). + it's 16x and if they ever change their mind, using the adena and stuff from their first char they farmed would make it extremely easy to farm a new one. Also, would it mean making a dwarf become a spellsinger as a main class and a crafter on sub? That would be almost game breaking...
What I think could be great solution to this would be donatable change of nicknames (if it isn't already planned) - if someone decides to change their main char, let them swap nicknames for few DEC (500? 1000?). I guest that should be easy to do in the database and wouldn't hurt anyone or anything.