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

itthinx

The plugin protects a site so that only members can access its pages.
Suitable for site lockdowns, private sites and sites that are under construction.
It allows to redirect visitors to a particular page or to the WordPress login.
Members who are logged in have access to the site. 
Members must belong to the site’s Registered group, or to a particular group as determined specifically for the site.
The plugin is an extension to <a href="https://wordpress.org/plugins/groups/" rel="ugc">Groups</a> which is required.
The redirection settings can be adjusted in Settings > Groups Blog Protect :
Redirection options can be set for the blog – or for each blog in a multisite setup:
<ul>
<li>no redirection</li>
<li>redirect to a specific post, note that with this option the blog is shown to the visitor but only that page can be visited</li>
<li>redirect to the WordPress login</li>
</ul>
The redirect status code can be selected among:
<ul>
<li>Moved Permanently (301)</li>
<li>Found (302)</li>
<li>See other (303)</li>
<li>Temporary Redirect (307)</li>
</ul>
Site administrators can determine which group is used to protect the site:
<ul>
<li>By default, users must belong to the Registered group to be able to access the site, so any registered user who is logged in will have access.</li>
<li>The constant <code>GROUPS_BLOG_PROTECT_GROUP</code> can be set in <code>wp-config.php</code> to indicate the name of the group to which users must belong to be able to access the site.</li>
<li>For multisites, the <code>GROUPS_BLOG_PROTECT_GROUP_n</code> constant can be used to indicate the name of the group required to access a particular site, where <code>n</code> is the blog ID of the site.</li>
</ul>

Groups Blog Protect

Protect access to blogs via group memberships powered by Groups.

Multisite Featured Blog vs Groups Blog Protect