Colby on the official forums posted a great build for leveling duel wield.
Pros: by far fastest DPS in game. constant morale generation and spamming skills. can still use a 2h for tanking. great for tanking or DPSing
Cons: less HP when tanking dual wield. requires lots of hit rate gear. cannot use for PvP
Though you could essentially tank with this build too all bosses except melee ones like Kermode, Tite, Khap. Swamp Fury is needed in main hand for this. CKD is best for offhand, but Claw or Seal are good substitutes also. Epic Trippers Robe is also needed for chest as well as the Precision Cloak. Everything else is pretty standard. The tanking spec for melee bosses will look exactly the same but take 3 points from Staunch and put into Feint. Your actual skill damage will be slightly less than with a vorpal (up to 100 dmg less on crits), but don’t be put off by the small numbers at first. They add up alot faster than a slow 2hander, and this build is by far the fastest and most DPS spec in the game. Mainly because of the morale generation that you get and being able to spam skills nonstop as a DPS and also more than double the white DPS of a 2h. You should have plenty of hit gear for DPSing. While tanking with defense gear, you still want to have at least 93-94% base hit rate. Lastly, you can always switch to Vorpal and not worry about hit gear and put on more stamina gear on for tanking too. There’s nothing to stop you here from using a 2h for easier tanking.