Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php	(revision 29735)
+++ wp-includes/user.php	(working copy)
@@ -600,6 +600,29 @@
 
 		// sorting
 		if ( isset( $qv['orderby'] ) ) {
+
+			/**
+			 * Sanitize and clean up include parameter before checking for contents
+			 * if it ends up empty after checking, we dont want to try to sort on nothing
+			 */
+			if ( 'include' == $qv['orderby'] && ! empty($qv['include'])) {
+				$include = is_string( $qv['include'] ) ? explode( ',', $qv['include'] ) : $qv['include'];
+
+				if ( is_array($include) ) {
+					// sanitize array for ID values
+					$include = array_map( 'intval', $include );
+					// cleaning up the unwanted values:
+					// filter out all 0 values
+					$include = array_filter( $include );
+					// remove possible duplicates
+					$include = array_unique( $include );
+
+					// please advice: use new variable or put back
+					// should the parameters be formatted more globally?
+					$qv['include'] = $include;
+				}
+			}
+
 			if ( in_array( $qv['orderby'], array('nicename', 'email', 'url', 'registered') ) ) {
 				$orderby = 'user_' . $qv['orderby'];
 			} elseif ( in_array( $qv['orderby'], array('user_nicename', 'user_email', 'user_url', 'user_registered') ) ) {
@@ -621,7 +644,10 @@
 				$orderby = 'ID';
 			} elseif ( 'meta_value' == $qv['orderby'] ) {
 				$orderby = "$wpdb->usermeta.meta_value";
-			} else {
+			} elseif ( 'include' == $qv['orderby'] && ! empty( $qv['include'] ) ) {
+				$include = implode( ",", $qv['include'] );
+				$orderby = "FIELD( {$wpdb->users}.ID, {$include} )";
+            } else {
 				$orderby = 'user_login';
 			}
 		}