kilt is the kilt of sewn flesh from meathook in normal Culling of stratholme. The headgear and shoulders look like quest rewards (1-60 levelling). I can recommend the addon MogIT for checking out and browsing items.
The shoulder piece is from the Flowing Water (Recolor) set.
It might also be the Cosmos Vestments rather than the Kilt of Sewn Flesh, even though they look quite similar. On second thought the Kilt matches the color better.