Hi Pietro,
please use the "django-cms" mailing list for questions about developing with django CMS. This list is about development of django CMS itself.
As for your question, I think this would be a great use case for nested plugins. Create a "ScheduledPublicationPlugin" with "date_from" and "date_to", which accepts any plugins as child plugin, but only renders them when the current date/time falls within the two dates, or if you are in edit mode (so you are able to edit the plugins before they are visible publicly). This way, you can schedule any kind of plugin for publication.
for more information.