Maybe as an item that you can upload as a texture, which can load in the chat as a 32x32/64x64 depending on the price, and a couple that are default, like 6 emotes that include tori, uke and thumbs up/down.
Thing is this needs:-
) New set of rules just for the emotes.
) More work from the ES artists, given they are the ones who'd make the texture for the default emotes.
) More code to be put, which means all those who use this need the latest version, or on Steam aka this is in-game voice chat all over again.
Agreed so I can spam 02 everywhere.