This is a very nice module to use with Quick tabs. In my application I have the comment form block in one tab and the comments view in another tab.

I don't see the need that each node type to have a comment block on it's own. I changed the code so that the comment block can used generically for any node type.

/**
 * Implementation of hook_block().
 */
function commentblock_block($op, $delta = NULL, $edit = array()) {
  switch ($op) {
    case 'list':
     $blocks[0]['info'] = t("Comment form block");
      return $blocks;

    case 'view':
      $block = array();
      if (user_access('post comments')) {
        $node = menu_get_object('node');

        // Only nodes dressed in page view are invited to this party.
        if ($node->nid) {
          // Only display the form if we are allowed to post comments.
          // Note that this works because this function is called before the
          // 'view' operation in hook_nodeapi().
          if ($node->comment > COMMENT_NODE_READ_ONLY) {
            $block['subject'] = t('Leave a comment');
            $block['content'] = drupal_get_form('comment_form', array('nid' => $node->nid));
          }
        }
      }
      return $block;
  }
}

I did not post this a a patch, as it is more like a feature request.