i invented a cool tool almost exactly like what your after..
I call it wctin mashups.. Its a video slideshow you can embed on your website. It contains 50 random "updated" videos for any given keyword, so you dont even have to update the code.
You will notice under the mashup is the name of my site
www.wctin.com, you can change that to display your sitename or message if you want.
You can also choose adult or non-adult results. The videos will be pooled from google video , youtube video and the rest of the net.
try it out here
http://wctin.com * click free mashups from the menu.