Vitalii

This plugin can to quickly switch user by click. It is comfortable for develop themes and plugins.
After load page, loading neat closed sidebar from right. By click on arrow it show or hide sidebar. Sidebar is 
displaying all registered WordPress users. By click on user is ajax send user ID to back end where switch user. 
After response is JavaScript reload page with registered new user.
<h3>Why using iBryl Switch User?</h3>
<ol>
<li>Quickly switches user by click.</li>
<li>Doesn’t slow down loading.</li>
</ol>

Plugin Name: iBryl Switch User

This plugin can to quickly switch user by click. It is comfortable for develop themes and plugins.

sevenspark

The Menu Swapper provides two utilities:
<ol>
<li>
A settings page that allows you to register unlimited menu theme locations
</li>
<li>
A meta box that will appear on Pages and Posts, which will allow you to replace existing menu theme locations with your new theme locations for those individual Posts/Pages.
</li>
</ol>
<a href="http://www.youtube.com/watch?v=kAd0_RKvvLw" rel="nofollow ugc">Video demo</a>

Menu Swapper

The Menu Swapper allows you to register custom theme locations and easily swap menus on individual Pages or Posts.

Plugin Name: iBryl Switch User vs Menu Swapper