The notion of customized search engines, or "search collections" as defined in an earlier post, already exists and is available to end users - see for example Rollyo, which allows you to "create personal search engines using only the sources you trust".
It shouldn't be too hard to implement a similar concept at the organizational level, For example, in a legal office, good Knowledge Management would imply that a process exists to centrally create, update and maintain subject based search collections. All lawyers using these collections instantly benefit and they can suggest additional search resources to be added to search collections, etc.
PS: On a personal note, I have switched from using Google to Jux2... Search results are more interesting (try it!). A Jux2 Firefox plugin is also available here.