Best solution to feature posts from a network of writers

Hey there,

I'm hoping to get some advice on how to achieve the functionality/process below. I'm going to describe my current set up but if you think I should set it up differently please share your thoughts.

I've got multisite/buddypress running my main site and nine sub-sites. Writers are allowed to post to all of the nine sub-sites if they'd like. Essentially with this set up we have a network homepage and each site has a homepage. For both the network homepage and the nine sub-site homepages, I need to be able to control which posts appear on their homepages.

So on the network homepage I'll be choosing which posts from across the nine sites appear on the network homepage, and for each of the nine subsites I'll be choosing which posts appear on those homepages.

I guess my question boils down to, which theme/plugin combination will get me to this set up?