Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php        (revision 29733)
+++ wp-includes/user.php        (working copy)
@@ -621,6 +621,9 @@
                                $orderby = 'ID';
                        } elseif ( 'meta_value' == $qv['orderby'] ) {
                                $orderby = "$wpdb->usermeta.meta_value";
+                       } elseif ( 'include' == $qv['orderby'] && ! empty( $qv['include'] ) ) {
+                               $include = implode( ",", $qv['include'] );
+                               $orderby = "FIELD( {$wpdb->users}.ID, {$include} )";
                        } else {
                                $orderby = 'user_login';
                        }