Dueling (1 vs. 1 or Team vs. Team)

I searched the forum and didn't find much discussion, although I know it has been talked about. But rather than open world (flag) PvP since that seems unlikely, I would like to see a dueling system added. It could take place anywhere in the world but you would engage in a duel via invite. It would be "Invite to Duel" or "Invite to Team Duel". I think it would be really cool to be able to have my FC members duke it out with each other. Or there could even be FC vs. FC battles. Nothing regulated, just a purely unrestricted brawl. There would have to be an "Ignore Duel Invites" option of course but it would be cool to just have battles for fun without having to go to the limited number of arenas to fight random people.

Just a thought though. I apologize if there is a similar post to this.