Extra richtext admin textfield for custom posttype with toolbar tabs?

Maby you should use the wp_editor instead? Then you have more control of the editor. An example if you have a meta box called “myfield” in the custom post type. If you want a simple editor you can do like this:

echo '<form action="" method="post" target="_blank">';
  wp_editor('<p>Some content</p>', 'myfield' );
echo '<input type="submit" value="Submit" /></form>';

If you want more control you can enable stuff in the array like this:

$settings = array(
    'wpautop' => true,
    'media_buttons' => false,
    'tinymce' => array(
        'theme_advanced_buttons1' => 'bold,italic,underline,blockquote,|,undo,redo,|,fullscreen',
        'theme_advanced_buttons2' => '',
        'theme_advanced_buttons3' => '',
        'theme_advanced_buttons4' => ''
    ),
    'quicktags' => array(
        'buttons' => 'b,i,ul,ol,li,link,close'
    )
);

echo '<form action="" method="post" target="_blank">';
wp_editor('<p>Some more content</p>', 'myfield', $settings );
echo '<input type="submit" value="Submit" /></form>';