Made by Marc Silverman. https://github.com/silverma/ToggleProxiesPlugin

A plugin for Adium 1.5 that makes it easy to turn all account proxies on or off with a key stroke.

In order to build you'll need to build adium and add the frameworks to the project as detailed here:

http://trac.adium.im/wiki/CreatingPlugins

You can download the built plugin here: https://github.com/silverma/ToggleProxiesPlugin/downloads

Once installed, the Toggle Proxies menu will show up near the bottom of the file menu.