Someone has. I saw them at D*con once. If I remember correctly the official 300 guys hated it. Some of them were all "that's not in the movie so you suck" and excluded her from their meetup.

Was an interesting thing to watch because being a cosplayer you always see fuckery from the inside point of view. Seeing it from the outside of a group really makes you realize how important it is not to be a dick.

Amazon Mandy did one I think.