As I spend seriously scary amounts of my life searching Microsoft.com and related properties, I threw together some OpenSearch thingummyjigs to search from the IE7 Search Box Thing.
I'm still unconvinced that they're more effective than just typing site:something.microsoft.com in every query (I don't have to take my hands off the keyboard to do that), but it was a fun learning exercise.
http://www.tristank.com/MiscFiles/Search/Searchproviders.htm for playing around...
Untested, unsupported, they-might-break-your-legs-accidentally, the usual disclaimers apply.
I've been thinking about doing a post on my google habbits; but in my mind no-one would really understand...
Ctrl+E to search! Alt+D for Address Bar!
A very cool web site http://www.OpenSearchList.com lets you review, customize and add searches using the method you outline here. Give it a try!