According to VG24/7, the new items will be available for Transmogrification presumably in the upcoming Legion expansion, which releases in August. First up is a gold and silver sword and shield combo, the latter of which is just fantastic looking, complete with glowing blue eyes and silver etchings. The second set features an Axe and Staff combo that has green fire spilling from the staff's eyes.
They're all pretty slick looking, and each will have its own achievements. To unlock the items you'll need to log in during the two month period after the film's premiere.