Abbas S

This plugin helps to create a widget and shortcode to create featured blogs.
Following are the things done
A settings page created for featured. 
You can enter the blog id in the blog id: text box in the settings page and click on get blog details button . 
This will fetch( by AJAX ) get the blog name , blog link , and blog Avatar ( based on the avatars plugin ). 
It will also add two buttons 
 Add this blog -> Which will add this blog to the featured blog list 
Can -> it will not add the blog to the featured blog list. 
Then saving the settings will save it. The settings are saved different for each blog . 
Then the user can use the widget as follows . 
Drag the widget on a widgetize area. 
Enter the blogids in the widget , then those blogs will be used as featured blogs. 
If nothing is entered in the bloglist the blog list from the settings will be taken. 
The user can use the short code as follows
The user can specify the blog list in short code argument. For e.g:- [multisite_featured_blogs blogids=”3,2″].The those blogs will be displayed in the featured blog list. 
If the user passes no argument then in case the featured blog list will be taken from the settings. For e.g:- [multisite_featured_blogs]
This plugin was done as a part of some work done for http://premium.wpmudev.org/ , but was later not released. 
Thanks for all the help for this plugin from WPMU Dev

Multisite Featured Blog

This plugin helps to create a widget and shortcode to create featured blogs

Boone Gorges

modemlooper

Andy Peatling

Give group creators and administrators on your BuddyPress install the ability to attach 
external blog RSS feeds to groups.
Blog posts will appear within the activity stream for the group.
New posts will automatically be pulled every hour, or every 30 minutes if someone specifically visits a group page.

BP External Group Blogs

Give group creators and administrators on your BuddyPress install the ability to attach

Multisite Featured Blog vs BP External Group Blogs