I have been lately looking at the open source CMS alternatives based on django. After some times investigating I have decided to give django-cms  a try.
django-cms provides an API to write plugin it is well documented  and you can also look the implementation of plugins listed there . I have decided to experiment with it by writing a plugin that displays the content of a feed into a page. The source code is available on my bitbucket account in a project called cmsplugin-feed. The development of this plugin has been relatively straight forward and once you get to know the conventions defined to implement an extension. You feel like you are writing python code for a django application. The CMS part does not stand on your way at least it didn't in my experimentation.
Here it is 2 screenshots showing this plugin in action :
In order to add a feed you need give a name and an URL to your feed
Then the plugin displays the field on a page.
I would be interested to read from someone the "best practice" to paginate the content of a plugin. Ideally I would like to add a parameter for every feed indicating how many items I want per page. Then I would like to paginate the feed in the placeholder of every page and this will allow the user to navigate between the pages.