I don't think that trying to make an inventory system where each item is priced out in Dash is the best way to go about this. Stores already have their own internal systems and the mere thought of trying to integrate with a separate inventory/pricing module for crypto would be a nightmare. Best bet is for the stores to do everything in their existing fiat system, with a checkout option that allows users to pay in crypto, and where that crypto is instantly convertible back to fiat (or automatically converted back to fiat by a third party). Dash has an advantage here because of InstantSend, since any instant conversion to fiat (whether done by the merchant or a third party in the middle) would be significantly less risky (and thus less costly) because of no doublespends. Now, the chances of such a solution being unique to Dash is less likely, but it's possible that a more currency-agnostic solution is possible, where the Dash option might have the lowest fees because of InstantSend.