I've thought of physical beauty as a component of CHA (and even started a topic on that subject about six months to a year ago), but likewise I've never seen the need for a Comeliness stat or a "beauty mechanic". I've always felt that character's can look however the player wants them to. If that means there are a higher percentage of beautiful people in the game than there are in reality, that's okay. There's also a higher percentage of Fireballs in the game than there are in reality. (I call it The Melrose Place Effect.)