Exploring Buildings Virtually (or Geodesign in Miniature)

I stumbled upon an application from FloorPlanOnline that targets the real estate market, but I think has potential applicability for many other domains. While doing some online house-hunting I came across a listing that included a great virtual real estate tour. The first thing that caught my eye was a map; actually a floor plan that showed the locations of photos taken at various places in the condo. I could click to see what things looked like from each location, and the icons changed color as I visited the photos; red was not viewed, green were those I had seen, and blue was the location of the current photo shown in the panel in the upper left.

I could also check how things looked when fully furnished by choosing objects from several menus with categories like bedroom, living room, kitchen, and also animals and garden objects. I could even drag and drop a golden lab in front of the fireplace (but somewhat disappointingly, could find no cats). Here was "GeoDesign" in miniature.

I've struggled to get similar floor plans and many other related kinds of maps into a GIS where I could manage objects that include links to photos, reports, and other media in a geodatabase. The struggle is that using a GIS all this works best if you georeference what you want to work with - a floor plan, a cave map, a site map for an archaeological dig - even if it makes no sense to do so, and your basemap is lower in resolution than the map you want to manage and (often by necessity) need to georeference.

I've evolved some workarounds to avoid the need to georeference maps of these types. But this is where I think GIS can take a lesson from CAD drawings - why can't we have a "paper space" projection that just treats scanned maps or vectorized diagrams in scaled page space, rather than UTM zone 12 or web mercator auxiliary sphere?