sortable selections in multi-select fields

The 'list' and 'sql' fields have a nice behavior for adding items to the field when it allows multiple items to be selected. However, it seems that the items are stored within their default order. I am not seeing a way to set the order. At the least, I would like to have the items ordered by the order I enter them (and by the way they initially displayed within the field). Better yet, it would be nice to allow the user to drag-and-drop the selected items into the desired order. (as an example, see the "sortable" demo on this page: www.jqueryrain.com/?Bxwy2bPt )

I encounter scenarios where this is desired (even required): Assigning multiple authors to a paper. Assigning multiple artists to an event. Assigning an organization's volunteers to various committees with each committee having different criteria for ordering.

I realize that this feature is not part of JFormFields, but it does add significant value, and having that as an option is not in conflict with Joomla standards ('sortable' would be an extension to normal JFormField).