As of the latest build, Beast Mastery, the 51 point Hunter talent in the tree of the same name that lets you tame "exotic" pets, remains unimplemented. However, it looks a sneak preview of the talent may have snuck into the patch all the same: Devilsaurs are now tamable!
The devilsaurs do shrink quite a bit, but are huge all the same -- I'd estimate the one I tamed was at least three times as tall as my dwarven hunter after taming. They also make a satisfying stomping sound as they run around behind you. They use the Ferocity talent tree (minus Charge for some reason), and eat meat.
They come with all the basic pet skills, use Bite for their focus dump, and have an extra family skill called Monstrous Bite. Monstrous Bite looks slightly unfinished, as there's only one rank, and it only hits for 4-6 damage. It's not completely bad though: It also has a buff on hit that increases the Devilsaur's damage done by 5% and stacks 3 times (It should be noted that Monstrous Bite's tooltip currently claims it boosts AP instead). In addition, the buff makes the devilsaur larger.
Gallery: Exotic Pets in the Wrath Beta
It should be noted too that Wowhead now lists chimeras as a pet category, complete with a family ability called Froststorm Breath. However, I could not personally tame the chimeras in Winterspring or Azshara.
[Thanks for the tip, Homelessbird!]