During this years Starlight Celebration I had enough gil to purchase the dream hat, but there's also a dream robe available.
In order to get the whole outfit you need to get a card from the moogles, the card needs to be traded to a specific job; War, Whm, Blm, Thf, Bst, Smn...and the cards have a level range also. So If you get a card for a BST level 60-69 you need to find a BST who has the card for your job and level. Not all that easy.
Last years Starlight Celebration I never got a chance to check out Windurst's decorations, so this year I made sure to visit.