Craftsman Wilhelm at Light's Hope Chapel in the Eastern Plaguelands wants 8 Frozen Runes, 16 Thorium Bars, 2 Arcanite Bars, 4 Essence of Water and 300 gold. You will also need to be of Exalted reputation with the Argent Dawn.
Thanks to you and Omarion (May he rest in peace), I am now able to create an Icebane breastplate. All you need to do is bring me the materials and pay a small crafting fee.
Here is your order, <name>. Delivered as promised!
The entirety of this quest happens at Eastern Plaguelands