Aether Ward. After all, this kind of magical ward doesn't seem like it exists in a traditional city, so why not exist inside some kind of alternate dimension, inside the dark aetheryte?

Do you propose that stalls and retainers be coerced into carrying only one type of item like they are now? I have an alternative suggestion:
  • Quantum stalls
Since the concentric rings expand or contract based on the number of stalls in them, why not have each stall exist in a quantum space that is only observable when a customer enters the appropriate ring? That is to say, if my retainer is selling both hats and shields, then her stall should be in both the hat ring and the shield ring. If she then also starts selling jewelry, the stall will also appear in the ring ring.

It's all magicky and teleporty to begin with, so why not use an organizational scheme that matches it?

/2gil