Created attachment 4111 [details]
Screenshot of the desired functionality
ExtendedPatronAttributes fields presently allow for Repeatable, Searchable, Unique ID, text type input box as well as auth_val driven select lists.
It would be nice to have a date picker calendar pop-up facility and ValidateDate() function for the field as its parameters
Possibly lib/C4/Members/AttributeTypes.pm, intranet/cgi-bin/admin/patron-attr-types.pl, intranet/htdocs/intranet-tmpl/prog/en/modules/admin/patron-attr-types.tmpl would require some functional changes
I've attached a screenshot of the feature. Right now I'm doing it with an ugly jquery hack via intranetuserjs (http://pastebin.com/BPQw43tY)