Slightly related thought: Why not design a store which allows instant fulfillment from a wide selection of goods while taking up less ground level space? I could see an Amazon/Walmart/etc store where you reserve the shelf space for presentation, but the goods are actually stored on higher floors and delivered to the customer upon checkout? Real-estate is a premium in many markets and probably keeps out super-center style stores. If you could build up, without having to extend retail niceties to all floors, you might make the costs work.