I am asking this because of following problem. jQuery file included in
WordPress is different from official one in that it has jQuery.noConflict at
it end. If we use jQuery from Google AJAX Libraries, there is noconflict so
we need to add it.

Author of plugin Use Google Libraries (which enables use of files from
Google’s servers) solved this by enqueuing file jQnc.js (which whole content
is jQuery.noConflict(); ) . It is lightweight but it needs another request
and headers could be up to kilobyte.

It would be better if noConflict code is added in html of page, it will not
increase page size, but it will remove one request. I asked Jason could he
enable this but he said that he is not aware of way to do this with WP API.

So, does anyone knows solution for this?

    if ( is_a( $wp_scripts, 'WP_Scripts' ) && in_array( 'jquery',
$wp_scripts->queue ) ) {

        if ( $wp_scripts->registered['jquery']->extra['group'] == 1 ) {
            remove_action( 'wp_footer', 'wp_print_footer_scripts' );
            add_action( 'wp_footer', 'my_print_footer_scripts' );
        }
        else {
            remove_action( 'wp_head', 'wp_print_head_scripts', 9 );
            add_action( 'wp_head', 'my_print_head_scripts', 9 );
        }

    }

    function my_print_head_scripts() {
        $rest = my_print_scripts_prep();

        wp_print_head_scripts();

        my_print_scripts_finish( $rest );

        wp_print_head_scripts();
    }

    function my_print_footer_scripts() {
        $rest = my_print_scripts_prep();

        wp_print_footer_scripts();

        my_print_scripts_finish( $rest );

        wp_print_footer_scripts();
    }

    function my_print_scripts_prep() {
        global $wp_scripts;

        $offset = array_search( 'jquery', $wp_scripts->queue );

        $rest = array_slice( $wp_scripts->queue, $offset );

        $wp_scripts->queue = array_slice( $wp_scripts->queue, 0, $offset + 1
);

        $wp_scripts->print_html = "<script
type='text/javascript'>jQuery.noConflict();</script>\n";

        return $rest;
    }

    function my_print_scripts_finish( $array ) {
        global $wp_scripts;

        $wp_scripts->queue = $array;
    }

Another possible approach is to create your own version of the
wp-admin/load-scripts.php script concatenator.

peace~