anyone had the problem where the customer stands outside and never walks into your shop?
Try setting your shop to 'open'? Look at the inside of the front door to your shop.
I had this bug occur to me too; reloading the game made him disappear.
I've had this problem too and if you haven't found a temporary solution already, I've found that if you bring a weapon just out of the front door they will come and grab it if its the weapon they want, if not bring a different type of weapon out until theytake it and leave then the next customer will come