Render Portals - few Cameras rendering a few rooms but can be projected to a plane in real-time to thousands of windows -shift main camera and..
This is about cameras targeting a couple areas and have them repeated rendered/projected in the scene on 3d models such as windows or TV so that when you move the main camera gets world coordinate perspective view/angle of all the local cameras. A skyscraper with a few materials that are random could give the users the appearance that there are actual rooms but they are decoys.
In the future for organization as an example, I can imagine a second stage for setting up office spaces to be projected as rooms etc or in the main stage area to potentially pass through portals. Render portals overall would increase the illusion of detail with less space & resources.
This effect should be made compatible with Render plugins.