Here's Push's armory btw.
The World of Warcraft Armory
And another guy who posted in the enhance thread awhile back, I think his 5v5 isn't active anymore but it was 2k+ at the time.
The World of Warcraft Armory
Push's 3v3 appears to run as Warrior/Healer[Paladin or Priest]/DPS[Enhance Shaman or Mage]. His 5v5 which is also 2k+ rated (or was last time I checked) doesn't even run with a warrior. My guess is that his 5v5 runs as Shaman/Mage/Warlock/Paladin/Shadow Priest, with a 2nd mage that swaps in for either of the casters. (there's a 2nd paladin on the team with 0 games played). I'm amazed that they can do that with 1 healer with an enhancement shaman on the team.
I'll also point out that Push runs as 0/45/19 and doesn't take the commonly assumed "pvp talents" in elemental. He hasn't placed any extra points in survivability (Toughness/Anticipation) but took 2/2 Ghost Wolf and of course improved grounding totem.