Develop an Extension System

[eluser]bohara[/eluser]
Hi All,
I am thinking about implementing a extension system for an application I wrote. Similar to what is done in expression engine or other extendable applications. Ideally - extensions would add core functionality to the application such as new top level navigation area with views, graphics, forms, etc. and would likely modify the views in other parts of the system.

I know it can be done, I've just never attempted such a thing. So my question is - Has anyone done this with CI? If so would you be wiling to share how you did it?

Thanks in advance.