Blade & Soul isn't the first title that springs to mind. Maybe it should, though, if a new video at MMO Culture is a portend of things to come.
The fantasy martial arts MMO recently added its first player-designed outfit, which for now is only available via ongoing Korean internet cafe events. The get-up is called the Ethereal Fairy costume, and the source links below feature some images and a bit more info. We've also embedded a video after the cut if you'd like to see the outfit in the finished game.