It's a simple Plugin to load a Theme for a special user based on IP, User-ID, category or User-Level.
I really appreciate this plugin.
this plugin is exactly what i want to use for temporary under construction or migration periods, load a different theme for different users (for example public vs logged in)
the minor problem with the plugin is that you have to manually edit the php file to your needs as opposed to having options in the admin area
as part of this, it contains default values so you better not enable the plugin before you make your changes
Short und simple