WP 3.7 offers a filter to be dropped into wp-config.php that will automatically keep plugins and theme updated.
add_filter( 'auto_update_plugin', '__return_true' );
add_filter( 'auto_update_theme', '__return_true' );
Read more about it in the codex:http://codex.wordpress.org/Disabling_Automatic_Background_Updates#Plugin_.26_Theme_Updates
Are WPMU DEV plugins supported by this feature, or does it only work with repository-based plugins?