WordPress-MU is an official modification for WordPress able to manage multiple blogs with a single installation. I have used it to set up a platform for school newspapers, supported by the Council of Coruña.
I use the main page of the system as a summary of all the newspapers, showing the active blogs and the latest news produced on them. For that subject I found two useful plugins: List all and Most recent posts. As their name states, the first one lists the public blogs of the system and the second one extracts the latest news.
I needed a more complex behavior from them, so I made some modifications. Basically, I replaced the two parameters that wrapped the list with a format string as used in printf-like functions. Now the user can control all the content inside the list item, not only the beginning and the end.
Here are the files. Hope they’re useful for someone!