To update this thread, 72% of the NCAA Division III membership voted this past weekend at the annual NCAA Convention to approve the use of a "non-binding standardized celebratory form" after the prospect has been accepted to a Division III institution. While the use of the form will be optional, only the standardized form provided by the NCAA will be permissible.
The other point that I think is very interesting, is that it can be used at any time after August 1, 2015 (when the rule change becomes effective) as long as the prospect has been accepted for enrollment to the college. While the form will be standardized, there is no standard "signing date or signing period" for the use of this form. I predict that will be changed at a future NCAA Convention, if not before.