[djbaxter]

Thank you, tbworld.

The file is actually /includes/blog_functions_shared.php

I commented out the line you highlighted

if ($modinfo['permissions']['adminpermissions'] & $vbulletin->bf_ugp_adminpermissions['ismoderator'])
	{
		DEVDEBUG('  USER IS A SUPER MODERATOR');
//		$issupermod = true;    // <-- Comment this out.
	}

plus just below that

	if (empty($do))
	{
		if ($issupermod)
		{
			// return true;  // <-- comment this out
		}
		else if (isset($modinfo['isblogmoderator']))
		{
			if ($modinfo['isblogmoderator'])
			{
				DEVDEBUG('	USER HAS ISBLOGMODERATOR SET');
				return true;
			}
			else
			{
				DEVDEBUG('	USER DOES NOT HAVE ISBLOGMODERATOR SET');
				return false;
			}
		}

I can confirm that this prevents both Admins and Supermoderators from being able to view private blogs.