http://virtuanews.co.uk/

It is used here at Techzonez. Not the easiest in the world to work with, very advanced stuff, but once you get the hang of it I think you will not find a better backend. Try the demo. I have a site at marketmynews.com that has some special pages, but I have drifted away from it, so don't look for anything up-to-date except for the homepage.

Hope this helps.