In my mind you could override default wrapper's view via Joomla template and insert code that will call JComments from overrided view.
1. Copy file /components/com_wrapper/views/wrapper/tmpl/default.php to /templates/
your joomla's template/html/com_wrapper/wrapper/default.php
2. Edit copied default.php and insert before line:
</div>
next code:
<?php
$commentsPath = JPATH_SITE.DS.'components'.DS.'com_jcomments'.DS.'jcomments.php';
if (is_file($commentsPath)) {
require_once($commentsPath);
$menus = &JSite::getMenu();
$menu = $menus->getActive();
echo JComments::showComments($menu->id, 'com_wrapper', $menu->name);
}
?>
You'll also needed to have JComments plugin to build correct links to comments posted in the wrapper. But at this moment I've no idea how it could be implemented (I'm not familiar with wrapper because I've never used it and don't know how its links looks like).