A front page devoted to announcements. Like XenForo and you hit forums to go to the forums.
You mean to say something like live stream of content ?
This should be possible with a combination of the planned page manager and widget system.
It's already possible in 1.8 for that matter, via portal.php.
I'm liking this idea...could very well be possible with everything going with MyBB 2.0.
This already exists within MyBB 1.8 in /portal.php however I'm not sure if it will be implemented within 2.0