If it can be fit that into the same dimensions we're currently using. The problem with any larger emoticons is that it would increase the line-spacing whenever inserted . Even these do that to an extent. Note the space above the line with the emoticon in this entry to see what I mean.
Of course, if anyone feels like making some themselves, feel free - just ensure they are the same dimensions and general look as the ones currently on offer.
That's 15px x 15px gif files for those aiming to get creative
yep! and I am looking to an emoticon of applause as well as a funny face which dribbles...