This isn't run by the Cosmopolitan Las Vegas, but it's as good as it can get. This webcam is mounted on the Polo Towers (a timeshare building). It's their view of the Las Vegas strip, but it clearly shows the front of the Cosmopolitan, and about 3/4 of the Beach Tower at the Cosmopolitan
Enjoy
http://www.polotowers.com/strip_cam.html
CondoHotel Forums
http://www.condohotelforums.com/article.php/2008080212250566