According to the News.com article a new video search engine, Truveo, is launching today. I haven't had much time to tryout the new engine but will try to spend some time with it soon. According to the story, Truveo finds and crawls material from the open web and from mainstream news sources by, "by analyzing visual characteristics of a Web page rather than just text." You can read more about how Truveo works here.
I did notice that Truveo recognizes MediaRSS and offers numerous advanced search options. Again, I haven't had time to run many comparison searches but did see that many of the "mainstream" news video sources (CNN, NY Times, BBC, etc) are also available from video engines like Blinkx, AOL Video, and Yahoo Video. Also, from what I can tell, Truveo doesn't offer "transcript search" of video clips. So, you're searching on metadata and /or blurbs about the content.
More in the article: Start-up Truveo enters video search field.