Order Status: Notifications about shipments

I want to be notified when my items ship. I'd like an email with the ship-to address, the project name, the line items and quantities, the tracking info.

I also want notifications if the "current estimated ship date" changes. 

We'd want customers to be able to control the volume of emails they receive. How could we allow customers to opt-in for notifications on some or all orders? Should it be one email sent at the end of the day about all the orderlines shipped for the account?

Notes:

1. Invoices are sent the day the item ships, but they do not have tracking info. 
2. A notification is sent to the person who submitted the PO if Allegion misses the ship date.