i think the screen real estate dedicated to smilies is already maxed out, and the existing ones each have fervent followers.
If I were ambitious, I would bookmark some websites that list hundreds of plain-text emotiocns AND define them.
(What nerds we Internetters be! Forming cryptic geek codes for emotions, and preferring to look them up and then make others look them up ... intead of expressing the emotions in English! Oh, well, whattayagonna do? Buncha engineers. Sheeze!
(didn't there used to be a "rolling eyes" emoticon??
Oh no! How will I express bemusement and disdain NOW!?!)