On a search for qwertyuiopasdfghjklzxcvbnm, I found that there was a 3D warehouse result in the results. I looked in the sketchup.google.com robots.txt and saw that there was no entry for /3dwarehouse/search? . There are some interesting domains there, though, like /call and /ie.
Search: http://www.google.com/search?q=qwertyuiopasdfghjklzxcvbnm
Robots.txt: http://sketchup.google.com/robots.txt

http://www.google.com/search?q=site%3Asketchup.google.com%2F3dwarehouse%2Fsearch
gets a ton of 3d warehouse searches. They should not be polluting their results with 3D warehouse searches like they temporarily did with blog search.

I wrote something about Google polluting itself:
http://googlesystem.blogspot.com/2006/06/search-google-searches.html