Custom fields for user's profile
AbleCommerce 7.0 has the back end support that Merchant could store customer information for a user that only the merchant would update on the user's/customer's profile. i;e; an account number, special note, cross-reference to another user, etc.
There is a User.Settings property, which connects to a UserSettingsCollection class. The data here is persisted to the database and associated with the user. It would be the natural place for this kind of data. If anyone wants to have custom fields for the users then he/she should make use of User.Settings. For any field that you want to be able to manage, you can add some UI to access and work with this field.