A field that displays a configurable mask such as *****9999 (displaying last four digits only) or ********* displaying no digits) but that would allow a user with appropriate credentials to enter or modify the SSN would be good. If the user is enabled for access under field-level security a fly-out prompt could be presented (similar to the composite address prompt on the Contact form) when the user clicks on the field. When user exits the prompt it would return to the masked display. We are using Sales for a financial services app, where this enhancement would be very useful.