Change top level menu item to point to custom submenu item

You can also change the menu with the global variables of WordPress for display the menu and submenu.
All first items are in the var $menu and all suparts are in $submenu.

Also a small example for change the order of the submenu-items with edit.php.
Add thius plugin and see the result via debugging. The function fb_cmp is only the logic for reorder, but you can define you custom order in this function, she is the callback for usort.

<?php
/**
 * Plugin Name: .my Tests
 * Plugin URI:  http://bueltge.de/
 * Description: 
 * Version:     0.0.1
 */

add_action( 'admin_init', 'fb_get_menu' );
function fb_get_menu() {
    global $menu, $submenu;

    var_dump( $submenu['edit.php'] );
    usort( $submenu['edit.php'], 'fb_cmp' );
    echo '<hr>';
    var_dump( $submenu['edit.php'] );
}

function fb_cmp( $a, $b ) {

    if ($a->value == $b->value)
        return 0;
    else
        return $a->value < $b->value ? 1 : -1; // reverse order
}

As hint the result in a screenshot.