it's very impressive but the guy admits that he has a long way to go. In its current form it would look great for planes about to land or helicopters flying about in MFS but the guy admits that it's no good for street views - yet.
There's an old but still live thread on this forum about a loco/building generator. Not dynamic however, just a way to create buildings and assets quicker than with gMax or Blender. What you've pointed us to would be fantastic if it could be made to work as a backdrop for both day and night scenes. How that would be done, or even incorportated into a layout is something else again. It is however - food for thought!
http://www.cs.tau.ac.il/~tommer/citygen/ - you can save this as vrml and import into 3d studio max and save it as a format usable by trainz. its just not very simple to do, though.
Rather a unique idea , and as you have stated " Other than a screensaver " , but possibly someone will be inspired and/or given an idea that will work in Surveyor ?