I have a newly developed add-in for Bridge which adds a number of selection features to Bridge. Among them is "Select Rated" which does what you originally asked for David. If you or anyone else is interested in being a beta tester for an early version of this tool, please send me an email at cwf @ the-friend-family.com.
This new add-in requires Adobe Bridge and Photoshop CS2 and is not yet available on the Mac (only Windows).
Thanks for you feedback. You wish has been granted (the Filter panel allows you to select files that have a specific label, or rating or keyword, amongst other attributes). Check out the free beta of Bridge CS3 (http://labs.adobe.com/technologies/photoshopcs3/)