There are items in game referencing Pandaren though.
Wowpedia:
"Chen's Empty Keg: Refers to the secret pandaren brewmaster hero Chen Stormstout who aided Rexxar in Warcraft III: The Frozen Throne."
"An NPC child, Justin, who walks around Stormwind and fishes with two other NPCs tells unbelievable stories, one of them includes him saying "It's true! People have seen them! Pandaren really do exist!""
"A Pandaren companion called [Pandaren Monk] is available at Blizzard Store."
"The Bag of Fishing Treasures (reward from Marcia Chase's fishing dailies) has a chance of dropping an item called [Fantasy Portrait]. The item's icon is a picture of a Pandaren's face."