Notification when Customer manually updates Custom Field

We have some custom fields that are user accessible/editable via the admin panel. Is there any good way to get a notification when the custom field is updated? In other words, can we have it so that all of the Email Alert Addresses receive an email when the custom field is updated?

The only way I have figured out so far is by setting up a Rule based on Customer Events where an email is triggered when:
1) Customer Data is changed
2) Custom Field XYZ = value ABC

The problem is that if we are waiting for the customer to be able to change the value between A, B and C and looking for an email, we receive a notification every time the Customer Data is changed.

What would be really beneficial would be a new Rule Engine Customer Event that is triggered off of something like 'A Custom Field is Changed'