They were ment to be event off and then made craftable at anytime. Though I like Pojo's idea.. and who says it has to be permenant? They could have it setup just like God given items, you trade a piece of gear in and then it comes out looking like your kingdom set. Though if you drop it or trade it, it takes it's original form again. That would also keep it kingdom locked.
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Hearing the music is like seeing the colors of trance and feeling the power of acid