Currently, the Kendo ListBox has methods to return -- the DOM Elements using items(); the Selected DOM Elements using select(); ALL of the Data Items using .dataItems() and a SINGLE dataItem using dataItem(selector).

An additional method that would be extremely useful for this control, would be to return the SELECTED DATA ITEMS perhaps using a method  selectedDataItems().

Here is a JavaScript function that can be used as a template for providing the functionality (of course, it needs additional error checking):

    function getSelectedItems(lstName) {
         var selectedItems = [];
         //var lstItems = $(lstName).data("kendoListBox").items();
         var lstItems = $(lstName).data("kendoListBox").select();

        $(lstItems).each(function (index) {
            var selected = $(this).hasClass("k-state-selected");
            if (selected) {
                var id = "#" + $(this).attr("id");
                var dataItem = $(lstName).data("kendoListBox").dataItem(id);
                selectedItems.push(dataItem);
            }
        });
        return selectedItems;
    }

In a control such as a ListBox that inherently requires the functionality of "selection" -- then your user community would definitely need a way to not only return the selected DOM elements but also return the selected dataItems.

Hopefully, we see this functionality added to the Kendo ListBox very soon.