Tralala,
I'm not really sure I would want to work that level of specialization into this modification. It's not something I would ever use and I see the use of that being very low. Perhaps if I got this mod to my super happy spot where I was proud of it and had nothing else to do, I might work up those tweaks, but it seems that what you are wanting is much more extensive then I could put time into doing at this time.
I'm hoping to truly just replace the yahoo group and similiar type mailing lists.
I think what you are wanting is not what I'm offering here. The bulk of this modification about 90% of it, is handling retrieving emails and putting them into posts. Something your not wanting to do, your just looking for the notification aspect.