MMO-Champion datamined the lastest build and found the following:
Mechanical Pandaren Dragonling - Bind on Use. Will this be the MoP CE pet? What on earth does a Padaren Dragonling even LOOK like? Black spots around its eyes and a white tummy; I'm giggling at the thought of a panda-patterned whelpling tbh.
Glyph of Shadowy Friends (Your shadow form extends to your non-combat pets.) - This is a minor glyph for priests, obviously, and I'm jealous like WHOA! How awesome will it be to have a little shadow form companion run around with you everywhere? Lucky duckies. Makes me almost wish I played a shadow priest. Almost. :P
And from Wowhead News:
Two tamer NPCs have been discovered, Steven LisbaneI think that's it for now! Back to Diablo 3 and my chicken loving Fetish Shaman. :D
and Julia Stevens .
According to Imthedci on WarcraftPets forums, there's a small quest chain to win a duel against Julia (located in Westfall). I haven't checked it out yet, but looking through the chain, it seems the same as the quests to learn how to heal and revive your pets that can be completed in Goldshire. Except this time it's against an actual tamer and not just a trainer.