Extending Application Controller

[eluser]AgentPhoenix[/eluser]
I did a search through the forums but couldn't find anything that matched what I was really looking for. I've read the user guide about extending libraries and I've extended helpers in my application already, but I was wondering if there's a way to extend an application controller.

For instance, I have a controller called main.php, but since the application I'm writing will be distributed, I wanted to give any potential developers looking to extend the system the chance to build on the controllers without actually touching them. If I update the application and they've modified the controller files, they either have to overwrite all their changes and do them over again, or they have to go through the controller line by line to see where I've changed things. To avoid this, I was hoping CI would allow me (or them rather) to extend my controllers in the same way that helpers and libraries are extended.

So, I have a controller called main.php with methods A, B, and C. Is it possible to create a file called MY_main.php that extends main and lets me add methods D and E so that when someone goes to main/d or main/e it pulls those methods from the extended class instead of having to go to MY_main/d or MY_main/e?

(I do realize I could have developers just create new routes for all these, but I was hoping there's a more transparent method of doing this.)