Notification chanel plugin needed

Request: Design of a notification Plugin

We need a plugin that has the following functionality;

The author of a new post must be able to select a communication channel. This can be SMS, EMail and/or Push Notification OR No notification at all.
Out of the system we need a list being generated that can be used by an external provider to send emails, sms or push notifications.
Hence, it should deliver a list of emails, mobile numbers or ….. depending on the selection made.

<– with this functionality alone we could inform users, ALL users, on a notification channel being selected by the author of a post.

But we do not want to inform ALL users.
We do want to inform only users that subscribed to a certain category.
So, the user must be able to subscribe to categories, the author must be able to select cat’s. (So far no rocket science).
This of course has to be combined with the notification channel that has been selected in parallel.
On top of this we want to see collapsing categories; There is a nice plugin available BUT that only creates collapsing cat’s on the user interface.
We want to see it also on the admin interface (otherwise it is too complex to find the right cat) and we want to see it on the widget where the user can select his categories (not working on “subscribe2” at the moment).

We are using the current WP & Buddy press version.

This is our goal, this is where we want to go.
Can somebody tell me if there is something like this already available ?

If not, then is somebody interested in developing such a plugin ? (Is this the right area to ask for this ? In case yes, then I will go deeper afterwards with contact & details)