I know for horde the books are in Duskwallow March but not sure on alliance side, There are really only specilty items for your helm and shoulders. that you can't get untill you have lots of rep with factions or otherwise.
There are shoulder/helm enchants, however they arn't readily available until level 70. There are Shoulder Enchants sold by Aldor/Scryers. There is a Tanking Helm Enchant sold by Keepers of Time, down in Tanaris.