We've already discussed the loot, but we now have official confirmation: It is badge gear, and the vendor is unlocked with the "Make Ready" quest from the smith herself after the Armory phase of the daily chain is unlocked. You're going to want to start saving up the badges now, though. the prices are as follows:
-150 badges for the two-handers, the crossbow and the one-handed caster weapons.
-105 badges for the main hand melee weapons.
-45 badges for the off-hand melee weapons.
-100 badges for chest and leg armor.
-75 badges for waist, belt, and foot armor.
-60 badges for the rings.
This is the PTR of course, so these totals could easily change, but if you want to get yourself some of this phat loot the moment the vendor gets unlocked on your server, you'll probably want to start planning those Karazhan runs and Heroic sessions now.
If you want to go check it out yourself, by the way, the portal to Quel'danas from Shattrath has been opened on test server as well, so you can just head to the center of Shattrath city and teleport directly there.
Thanks to our various tipsters for the heads up.