I'm looking for a similar solution.
Due to bandwidth constraints, I don;t want visitors to have to refresh each time they want to see new posts. To give you an idea of the problem, if you go to the celticquicknews site, you'll see that there can be upto 800 'comments' per day on each article, and with people refreshing everytime as the total posts gets longer, it just eats up bandwidth.
I like the way Disqus updates your own comments immediately, so I'd be looking for something like that, except everyones comments should appear immediately (and without the refresh).
I'm thinking maybe some kind of RSS solution would be required, but displaying on the main site.
or maybe one of the vertical comment scrollers customized to full screen.
Can anyone point me in the right direction?