3d environment construction times

I've been having real difficulty trying to find real-world figures for how long it takes artists to create 3d environments. Does anyone out there have experience creating these environments regularly?

The kind of information I'm looking for:

• an image of the constructed scene,
• the tools used (Maya, Max, Sketchup...),
• an estimate of the number of hours using each tool.

These figures would really help the motivation of procedural tools for the rapid construction of cities. With a bit of luck (and a few more years research...) creating virtual repetitive architecture manually will be a thing of the past.