Holy/disc priest + 4 demonology locks (all undead)
Look up Dondiego/Donbartolo on Magtheridon on wowarmory for specifics.

Full clears/kills at the following levels:
RageFire Chasm = 16
SFK = 26
BFD = 27
Razorfen Kraul = 29
SM Library = 34-36
SM Armory = 36-38
SM Cathedral = 38-40
Razorfen Downs = 40-42
Uldaman = 45
Zul'farrak = 47-48
Maraudon = 49
Scholomance = 60
Arazzius the Cruel = 60 (lost 3 of 4 felguards)
Natural Remedies = 60 (lost two felguards when two raging behemoths added towards the end)
Stratholme = 61 (live side cleared; doing dead side tonight)

Updates:
--> Hellfire Ramparts at 61 = wipe on Nazan. Rest of the instance was ezmode. [update2] Finally went back and did it at 68. Trivial.
--> Blood Furnace at 68 was fine. The technicians in there AoE the pets down quick with the bombs though. Fear-kite FTW.
--> Underbog at 68 = easy/hard. The first time is difficult. Wiped on Hungarfen twice, then killed him with only one pet down. Next two bosses were pretty easy. Black Stalker wiped me the first time because of bad positioning triggered early aggro before I was spread out. 2nd run lost one lock but otherwise was easy mode.

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New group: 37 prot pally + 4 fire mages (will be PoM/Pyro spec at 41)

RFC = 18, took about 25 minutes. AoE = Win. No deaths.
WC = 20. Took about 90 minutes. No deaths.
BFD = 26. Took about 80 minutes. No deaths.
SFK = 27. Took about an hour. No deaths.
RFK = 30. Took about 80 minutes (mostly for the damn tubers quest). No deaths.
Starting SM tonight at 37. Will update when done with that.