Many projects make the project list difficult to use

We will have hundreds of projects but at that scale the project list drop-down will be difficult to use. Anything over 10 items in a drop-down starts to get unfriendly. Is there a different UI widget that could be used to navigate to a different project? I suggest having an option to replace the drop-down list with a Switch Project "button". When pressed you could do a DIV overlay that pulls in the project names in any number of ways. An Ajax search or category filter could even be used to limit your choices.

Note that I'm not suggesting multiple projects as other requests have. I just need a better way of selecting a single project.

We could filter the list using permissions but we would prefer that everyone have at least read-only access to all projects by default.