More Unknowns courtesy of this year's Summer Comiket!
If I had to guess, I would say she’s Sheryl Nome from Macross Frontier. If not, perhaps one of the pirates from One Piece, but I looked through some of the main characters from that series without much luck as to who this cosplayer is portraying to be!
Anyone got a better idea? Thanks to Alfred for sending this in!
EDIT: Thanks to anon for letting me know she is Bonne Jenet from the King of Fighters XI!