Didnt some merc solo him awhile back?
Solo'ed quite a while ago by a guildie, all be it using clever use of game mechanics (Still don't understand how he didn't fall to sleep lol).
As for "legit" 2-mans I'm aware of it being claimed on my server before recently, not really too sure what setup they used. However, having done the maths the dps requirements are 2729dps to beat enrage which overall shouldn't be too difficult if the healer can manage 800ish dps. A Commando spamming Charged Bolts w/ Superchared up should be able to match this and meet the healing requirements.
Never the less I don't think many have done it, so congrats