I just found out today that the pet you could get for participating in the mountain dew promotion is now sold by a vendor in dalaran.
Vendor name: Jepetto Joybuzz - Jepetto Joybuzz - NPC - World of Warcraft
It still says in the Mounts and Pets page that he is a promotional pet so if this is a recent change or if it's a bug, I do not know. But for all you pet collectors out there, go get yours today!
And sorry to everyone trying make money on these, but they are soulbound and cannot be caged.