Just a few random thoughts - these are the possibilities I'd consider if I were constructing a Market place set for greatest appeal to average poser users... I'd think making floor and walls separate and/or in sections would have positive appeal, that way the width of the hall could be controlled by the users. They could also choose to have doors down both sides, windows down both sides, one of each, or even blank walls as they choose. A couple of extra walls to place beyond open doors to simulate rooms would be good. I'd think a morphable prop format would be best - just a couple of dials for opening and closing doors and windows. Add the option of either an intersecting hall at the end, a blank wall, a window, a room door, french doors, dead end with laundry chute, or fire exit for added versatility. If you texture the walls, floor, and molding/trim separately it would help increase the variations possible, so it cloud appear as wood paneling, painted walls, or victorian cut-velvet wallpaper. Perhaps "grunge" or grimy texture variants could be included as well for a seedy atmosphere. A couple variations of light-fixtures would be good, Victorian gas-fixtures, old-style light-bulb sconces, and sleek upward-pointing "fan" lights are the three possibilities suggest themselves to me. And always include one or three pre-assembled setups for customers who have no interest taking the time to "do-it-yourself" with a new product they've paid for. Remember - there's 8-10 times more people who'd pay to have pizza delivered ready-to-eat, than to cook one from scratch. ..Just my 2 cents worth.....