Hidden Fates Elite Trainer box is now back up on Pokemoncenter.com (currently unavailable). It was taken off a couple weeks ago. One can assume that they are preparing to release it again.
AJ Toys & Books on Twitter: "Pokémon Hidden Fates Elite Trainer Boxes have just landed. We will processing everyone's pre-orders over the next few days. #thewaitisover https://t.co/DybhSjwp36" / Twitter