I posted about exactly this concept back in 2008. Briefly stated, I think it's a bad idea. Why? Because well-designed plugins should not scream "I'm a plugin!". The best designs are integrated into the interface in such a way that, if you hadn't just installed the thing, you'd never guess it wasn't part of the core software.

In other words, the plugin should put its interface page wherever it makes the most sense for that... whatever... within the menus.

My original post is here: http://striderweb.com/nerdaphernalia/2008/06/on-plugin-design/