scribu

AppThemes

With this plugin, super-admins can:
<ul>
<li>view any theme on any site, without enabling it</li>
<li>access any site through Admin Bar -> My Sites, without having a role on it</li>
</ul>
Intended for <a href="http://scribu.net/wordpress/the-future-of-multisite.html" rel="nofollow ugc">small Multisite installs</a>.

Hyper Admins

Simplify administration tasks for super-admins.

feedmeastraycat

WordPress removes the Update Services ability (Settings – Writing) when you create a network (aka enables WordPress MU/Multisite). 
Activate this plugin to get it back.
Note: This is only for WordPress setups with a network, aka multiple sites, aka multisites, 
aka WPMU in WordPress 3 and later.
This plugin might work with older WordPress MU sites. I haven’t tested it though. If you do, please 
let me know how it turned out.
<h3>Files</h3>
<ul>
<li>/activate-update-services/activate-update-services.php</li>
<li>/activate-update-services/README.txt</li>
</ul>

Activate Update Services

WordPress removes the Update Services ability when you create a network. Activate this plugin to get it back.

Hyper Admins vs Activate Update Services