In The Tempest, inside The Workbench.


Grenoldt will, after you get to 80 AND finish the appropriate Tank, Physical DPS, Magical DPS, or Healer role quests, you have this selection.


Inside each selection, is Job specific gear, that you can select, even when not on the correct Job, as long as you have it unlocked. Here my level 76 MNK is trying to grab the PLD weapon. You get a pop-up! Go ahead and grab it.


You are able to see what gear you currently have on you (Owned) or not (Available). And here is the SMN specific chest piece.