I've always liked the way that barter stands allow people to trade, but I also think it would be cool to see it taken to the next level. I think that we should be able to be shops, which would look like stone steads but with a sign hanging over the door, that could be customised when the builder finishes building it. Inside it would have a counter or similar stand for displaying goods, while the rest of the store can be customised as the owner wants. One small gate leads to behind the counter and only employees, that is people who are given permissions by the owner are allowed to go, others will need vandalism to break the gate and doing so will leave a vandal scent.
In the main room of the shop, people can enter and leave with no problems, but cannot take anything(including wall hangings, cupboards, items in containers) without permissions. The basement and attic can work as storage/living area for owner. The counter will work like a much bigger barter stand. Also, a special store owner version of a "bond of blood and soil" is held by the owner, and requires a LP cost to upkeep.
I also thought about having the builder be able to design the counter, so that it can be spread around the main room.