Quest Chains for Black Rock Spire

Lower
(Burning Steppes) En-Ay-Es-Tee-Why
(Burning Steppes) Kibler's Exotic Pets
(Burning Steppes) Mother's Milk
(Badlands) Operative Bijou
(Burning Steppes) Put Her Down
(Chain from ZF, Tanaris) The Final Tablets
(Badlands) Warlord's Command (Onyxia key start)

Upper
(Burning Steppes) Broodling Essence --> Egg Freezing
(Winterspring) The Demon Forge

Quest Chains for Dire Maul

East
Lethtendris's Web
Pusillin and the Elder Azj'Tordin
(Moonglade, level 56) A Reliquary of Purity -> Shards of the Felvine

North
Elven Legends

West
The Madness Within

Tier 0 drop locations

For quickish reference, here are the names of the bosses that drop the tier-0 set pieces we need.

Tier 0 drops

	Druid	Priest	Rogue	Shaman	Warrior
Head	Darkmaster Gandling	Darkmaster Gandling	Darkmaster Gandling	Darkmaster Gandling	Darkmaster Gandling
Shoulder	Gizrul the Slavener	Solakar Flamewreath	Cannon Master Willey	Gyth	Warchief Rend Blackhand
Chest	General Drakkisath	General Drakkisath	General Drakkisath	General Drakkisath	General Drakkisath
Wrist	BoE from Strat/Scholo?	BoE from Strat	BoE from Scholo/Strat?	BoE from Strat/Scholo?	BoE from BRS
Hands	BoE from BRS	Archivist Galford	Shadow Hunter Vosh'gajin	Pyroguard Emberseer	Ramstein the Gorger
Waist	BoE from Scholo/BRS?	BoE from BRS	BoE from BRS	BoE from LBRS	BoE from Strat/LBRS
Legs	Baron Rivendare	Baron Rivendare	Baron Rivendare	Baron Rivendare	Baron Rivendare
Feet	Mother Smolderweb	Maleki the Pallid	Rattlegore	Highlord Omokk	Kirtonos the Herald

Wrist, gloves, and waist are all BoE, and mostly drop from random trash in some zones.