I recently came across the site that sells a 3D model of Denver or particular blocks. I do not know how much it is or how different the models are from Google Earths models. I would down load the sample to get an idea first, but if you need a quick city with streets, sidewalks, buildings, and a elevation map, here you go.
Here is a link to the Denver details PDF.
http://www.fugroearthdata.com/pdfs/city/FCT_Services_CMV-Denver.pdf
And here is their main site. http://www.fugroearthdata.com/
Fugro EarthData's 3D city models incorporate all of the important massing details of a city's buildings, along with topographically accurate ground features. Our city models are comprehensive in both detail and coverage, providing professionals in media, architecture, urban planning, engineering, and government markets a powerful tool for understanding urban geography.
