Jacke's Chest piece.

[AdamFyi]

It is available... at least the design is. You can get it from Tam-Tara Hard, Stone Vigil Hard, and Hullbreaker Isle. There's two variants; one for monk (which is shared with ninja) that is red in colour, and one exclusive for bard which is white in colour.

The monk one drops from Tam-Tara Hard and Stone Vigil Hard. The bard one drops from Hullbreaker Isle and Tam-Tara Hard. Both drop from the chest of the final boss.

P.s. They're undyeable.