Yes! I actually completed it a few days ago.
Here's what to do, you'll first of all, need to respec into a very special build:
http://www.wowhead.com/?talent=bVcbkhxtbZfxx0f0qi
The idea is simple, it's a build that gives you maximum regen.
Use renew whenever possible, and just flash heals. Bring regen oils, regen food and ofcource, a mana potion. Potion sickness applies here as well.
You got holy nova, use it on the skeletons. Also remember to use Cure Disease on those who needs curing.
I usually play shadowpriest, but I had to respec into this build to do it, it was simply impossible as shadow.
You'll likely need 1-3 attemps, but no worries, that's nothing to be a shame off.
Good luck and enjoy your staff!