Since there is, as far as we can tell, only one adra dragon in the world, it seems unlikely that all Superb armors require one...more likely, there's alternatives (parts of other dragons, maybe? The brain of a vithrak elder? Blood of a powerful ogre mage?). I also always figured that the thing with the adra dragon scale or sky dragon eye or whatever was a "quick way" to enchant things. Perhaps there's a longer, more drawn-out system of rituals with lots of apprentices and equipment and 7 days of chanting that can do the job using 10,000 xaurip tongues instead.