Edit: Wowhead has an article with info and locations of all of the boss pets:http://www.wowhead.com/news=209945/5-2-ptr-new-elite-and-and-collectible-battle-pets
Looks like the new "boss" pets are on the PTR! Thought I'd make a thread showing what I've found so far. If you have anything to add, please do!
As shown in the pictures, the fabled pets have yellow paw prints above their heads instead of green, so they're pretty easy to spot.
You can currently fight them without being on the quest (though this may change). They seem to have normal pet moves, but are much stronger. Pets don't copy to the PTR at the moment so I couldn't properly test the battles.
Now for the pets themselves!
Ka'Wai (Credit to Petopia for the pic)
Map Location: N/A
Valley of the Four Winds:
Map Location: http://img708.imageshack.us/img708/9324/dosrygamap.png
Ti'un the Wanderer
Map Location: http://img195.imageshack.us/img195/4547/tiunmap.png
Vale of Eternal Blossoms:
Map Location: http://img827.imageshack.us/img827/5416/nonomap.png
Will update the thread as more info arises.
Last edited by Wamo
on January 14th, 2013, 11:18 pm, edited 4 times in total.