The game designer in me thinks you should think more about the dice. If you only care about an equal 50/50 split (you only care about a "ping" result or a "non-ping" result, and each are equally likely), why are you rolling d6's? You could just as easily flip coins. Maybe include an exploding die result on a 6? That's just me nit picking.

You mention limiting the number of "re-rolls" based on the size of the community. I'm not sure what you mean by re-rolls here. I think a solution to what you are trying to articulate there is having a cap on Price in certain locations. For example, a small hamlet might not be able to pay more than Price 3 for any goods, so you couldn't get huge windfalls from them.