Ornate Mithril Shoulder

The Ornate Mithril set was available from the Mithril Order quests, a long and expensive quest chain from vanilla for blacksmiths.

Sadly it was removed in Cataclysm, so finding a crafter for this set can prove to be difficult. It's really easy to find crafters in the armoury, though not many people realise this.

Look up any old (but still active) guild from your realm on the armoury. In the roster, use the drop-down tab on the right side where you can view professions (it shows achievements by default). From there click on the each character and search within their recipes for 'ornate mithril'. It's tedious, but much more efficient than spamming trade! :)