How hard would it be to work something like http://dev.wikia.com/wiki/EmoticonsWindow into MediaWikiChat? Probably behind a parameter or as just something one can add to a JS page like Common.js or Vector.js
I don't currently know any JS but if it isn't to hard to implement it I'd be be willing to try. I was thinking version 1.2 would be the best starting point since it's the last version that doesn't use Wikia's method of parsing emoticons.