How about instead of just having a shop counter be the shop in its entirity, one could actually mark the building as a shop if the public sales tech has been researched, to allow customers to purchase from all storage containers within.
Pros: All storage containers in the building can be used for selling things such as rum barrels, weapon and armor stands and the like.
It would streamline the current production stages a little more, because you could put one rum barrel in a private house for yourself, and then another one inside the shop- Basically meaning any overflow from your production automagically goes into the shop, removing the need for a hauler job as everyone does it part-time.
Cons: Takes time to implement? I honestly can't think of any.
Ways to accomplish this: You can work the option to make a building a shop into the public/private button.
Preferably the building would still require a shop counter- They gotta pay somewhere, right?
Production lines could prefer placing their output in non-shop buildings?
You could have the shop require someone in the building to man it, to balance out not needing a hauler character?
Ways to improve upon this later: Have customers grab things from containers, bring them up to the shop counter to pay for them there.
Allow traders to sell things to the shop counter, making it a general shop storage?
Add a haggling/charisma skill- Your cashier sells items for less and buys items for more than a veteran haggler, making more of a profit the higher the skill is.
Discuss!