Hi,
I am Nallakumar. I have more than 10 years of experience in developing AddIns for MS Office products.
As suggested by you, we can create a OneNote AddIn using VB .NET that will create a Ribbon tab in OneNote Ribbon. That tab will have 2 buttons.
The first button will be named "Send" and upon clicking this button will send the current page to list of pre-defined recipients.
The second button will be named "Settings", this will show a form where you can enter the Email List.
Thanks,
Nalla