What is the best way to build Plugins using CakePHP

Hi there,
I have an application which is available both in cloud and Opensource versions. In opensource version we have just given the basic functionalities. In cloud version we have a lot of features added. On public demand we need to create some custom plugins of each individual features. We have done it according to the cookbook 2.0. But for some plugins we need to change the basic controller and ctp files. And for now we have stuck with a lot of combination of plugin files. What is the best way to create a custom plugin in CakePHP and which method we should follow to give those plugins to our opensource users to installation it in there server where they have already installed our application? Can any one one help me with this?