This is something that we have been asked before, however there is no plan for this as these are deemed to be a rare item in the game, which is why you can only obtain them from the Spire of Eternity. In a similar way that Blueprints can only be obtained from the 10th Chest of the Tournament.
@FieryArien I understand what you mean there, but technically your paying Diamonds as an alternative. What we're saying is you cannot purchase Blueprints themselves as an item for you to store and use, as and when you require them