Samuel Mello

This plugin was designed to create virtual micro-sites that employ different themes while using the same content from one source. It uses WordPress’s rewrite rules to decide which theme to display to the end user based off of the url they visit. This will allow you to access the same website in a virtual sub-directory with a completely different theme displayed.
REQUIRES PRETTY LINKS TO BE TURNED ON

Cameleon

Virtual Microsite Creator & Multi-Theme Enabler for WordPress

xxxx7

This plugin adds Theme menus in the admin bar. 
You can switch and activate the theme on the admin bar. 
You don’t need to go to the administration screens to switch the theme.
(For Japanese User) 管理バーにテーマメニューを追加します。 管理バー上でサイトテーマの変更・有効化が行えます。 テーマを変更するために管理画面に行く? 要がなくなります。

Switch theme on admin bar

This plugin adds Theme menus in the admin bar. You can switch and activate the theme on the admin bar.

Cameleon vs Switch theme on admin bar