Icy Mooncloth

Here's a set based around the Mooncloth Robes for a Frost Mage or healy Priest.

Royal Headband Green BOE
Regal Mantle Green BOE
Mooncloth Robe Made by tailors
Ebonweave Gloves Made by tailors.  They are long enough that most bracers shouldn't show.
Mindfire Waistband Drops in the Blood Furnace
Staff of the Unknown Road Quest reward from Zul'Farrak
Regal Boots Green BOE

Alternate version

Underworld Mantle Drops in Ulduar 10 normal
Grand Magister's Staff of Torrents Drops in Sunwell Plateau

Alternate Shoulders

Khadgar's Shoulderpads of Triumph Alliance Mage Tier 9

Merciless Gladiator's Mooncloth Mantle Priest-only PvP reward.  The token to buy this drops from Void Reaver in the Eye.

Sanctified Crimson Acolyte Mantle Priest Tier 10

All details here.