what's the best way to decorate a page_controller so that i can add another allowed_action?

ultimately, i'm building a widget for the blog that needs to use a new action on blogholder (like the tag cloud does), but whenever i decorate page_controller, it says i cant do that because page_controller doesnt extend DataObject. i dont want to hack the blog module for upgrade reasons.

Any advice would be awesome.

thanks!
-Chris

class MySiteWideControllerMethods extends Extension{

//Page_Controller = $this->owner
}

//config.php

Object::add_extension('Page_Controller','MySiteWideControllerMethods');