I'm pretty sure they arent printing anymore. It was a good marketing idea bc then the decks become rarer and thus worth more money. Plus, since people knew they wouldn't be available again they bought them up as fast as they could. I think they may be giving away in some contests in the future, they have recently
It's a matter of marketing and branding. By having a very limited deck that's only available by gift or contests, they have created a mystique around that deck and thus themselves.
As a few of you have said, the White Centurions are reserved for contests and giveaways. I went ahead and locked this thread since it's starting to go off topic. PM me if you have any questions. Thanks.