Unfortunately, before the lovely /map emote was added as part of patch 4.1, the last time new emotes were added to the game was as part of the Wrath of the Lich King expansion pack. That was more than three years ago.
Personally, I'm a big fan of NCIS, and I would love a /headslap animation. What do you think? What new emotes should be added (keep it clean!)?
Editor's Note: WTB /doublefacepalm, for when one /facepalm just isn't enough.