Sergey Biryukov

WordPress Multisite (3.0+) already comes with theme and plugin editor enabled by default. This plugin is available for reference only.
Allows to enable theme and plugin editor for site administrator in WordPress MU. 
Requires Site Admin capabilities, not just blog administrator.
Based on the <a href="http://www.clickonf5.org/wordpress-mu/enable-theme-plugin-editor-wordpress-mu/5790" rel="nofollow ugc">non-plugin solution</a> by Sanjeev Mishra.

Enable Theme and Plugin Editor (WPMU)

Allows to enable theme and plugin editor for site administrator in WordPress MU.

Syed Balkhi

Awesome Motive

benjaminprojas

WP Editor is a plugin for WordPress that replaces the default plugin and theme editors as well as the page/post editor. Using integrations with CodeMirror and FancyBox to create a feature rich environment, WP Editor completely reworks the default WordPress file editing capabilities. Using Asynchronous Javascript and XML (AJAX) to retrieve files and folders, WP Editor sets a new standard for speed and reliability in a web-based editing atmosphere.
<h4>Features:</h4>
<ul>
<li>CodeMirror</li>
<li>Active Line Highlighting</li>
<li>Line Numbers</li>
<li>Line Wrapping</li>
<li>Eight Editor Themes with Syntax Highlighting</li>
<li>Fullscreen Editing (ESC, F11)</li>
<li>Text Search (CMD + F, CTRL + F)</li>
<li>Individual Settings for Each Editor</li>
<li>FancyBox for image viewing</li>
<li>AJAX File Browser</li>
<li>Allowed Extensions List</li>
<li>Easy to use Settings Section</li>
</ul>

WP Editor

Great editor, just the visual could be updated (maybe fix fullscreen mode)...

Good

The plugin works well, better than the default plugin/theme editor.

My only suggestion is that the editor area should be adjustable, it is not high enough.

Great, works well

WP Editor is a plugin for WordPress that replaces the default plugin and theme editors as well as the page/post editor.

Enable Theme and Plugin Editor (WPMU) vs WP Editor