Tom Lynch

Switch Theme allows WordPress Network Administrators to switch all the themes on their WordPress installation to a different theme in only a few clicks.
This is particularly useful if you have large network of blogs which you wish to switch to a new version of your theme.
If you find this plugin useful please <a href="http://supportus.cancerresearchuk.org/donate/" rel="nofollow ugc">donate to Cancer Research UK</a>, and let me know what think you via <a href="http://tomlynch.co.uk" rel="nofollow ugc">my website</a>.
Switch Theme is only for use with WordPress installations with multisite enabled, it will not work on standalone installations or WordPress MU.

Switch Theme

Switch Theme allows WordPress Network Administrators to automatically switch all the themes on their WordPress installation to a different theme.

Remi Corson

Choose a theme for logged-in admins only! This is a fully transparent method for all other visitors. This is a great way to work on a theme while visitors see the default theme.
<a href="http://remicorson.com" rel="nofollow ugc">Developer Website</a> – <a href="http://remicorson.com/easy-admin-theme/" rel="nofollow ugc">Plugin’s Page</a>

Easy Admin Theme

Tested up to 3.4 Stable Tag: 1.0 With this plugin you can can specify a theme to display only for logged-in administrators.

Switch Theme vs Easy Admin Theme