Wordpress - Create a custom admin page for custom post type + taxonomies + metas

This is how it can be done:

add_action('admin_menu' , 'add_to_cpt_menu'); 

function add_to_cpt_menu() {
    add_submenu_page('edit.php?post_type=name_of_post_type', 'Custom Post Type Admin', 'Custom Settings', 'edit_posts', basename(__FILE__), 'cpt_menu_function');
}   

You will need to start reading about the setting and options API, and then pull your CPT and Taxonomies into it.

Have a start here:

• Creating Options Pages « WordPress Codex

• Settings API « WordPress Codex

  • WordPress Settings API (options page) Generator

• Class Reference/WP List Table « WordPress Codex

  • Custom List Table Example Plugin - A practical example of WP_List_Table in plugin form

• Create a Custom WordPress Plugin From Scratch

• Administration Menus « WordPress Codex

  • Admin Menu Editor Plugin - allows adding, deleting, hiding, and re-ordering of administration items