[WhaLberg]

well, no need to fight. i do not agree this is something so needed, however i'd like to help.

as vb doesn't provide a hook for the additional query entry, you'll need to make a file edit.

find the following codes in private.php. use a php editor so you can see the line numbers as there are 18 $pms variable defined in the private.php
starting: line 1629
ending: line 1639

PHP Code:

// query private messages
        $pms = $db->query_read_slave("
            SELECT pm.*, pmtext.*
                " . iif($vbulletin->options['privallowicons'], ", icon.title AS icontitle, icon.iconpath") . "
            FROM " . TABLE_PREFIX . "pm AS pm
            LEFT JOIN " . TABLE_PREFIX . "pmtext AS pmtext ON(pmtext.pmtextid = pm.pmtextid)
            " . iif($vbulletin->options['privallowicons'], "LEFT JOIN " . TABLE_PREFIX . "icon AS icon ON(icon.iconid = pmtext.iconid)") . "
            WHERE pm.userid=" . $vbulletin->userinfo['userid'] . " AND pm.folderid=" . $vbulletin->GPC['folderid'] . " 
            ORDER BY pmtext.dateline DESC
            LIMIT $startat, " . $vbulletin->GPC['perpage'] . "
        "); 


replace it with:

PHP Code:

// query private messages
        $pms = $db->query_read_slave("
            SELECT pm.*, pmtext.*
                " . iif($vbulletin->options['privallowicons'], ", icon.title AS icontitle, icon.iconpath") . "
            FROM " . TABLE_PREFIX . "pm AS pm
            LEFT JOIN " . TABLE_PREFIX . "pmtext AS pmtext ON(pmtext.pmtextid = pm.pmtextid)
            " . iif($vbulletin->options['privallowicons'], "LEFT JOIN " . TABLE_PREFIX . "icon AS icon ON(icon.iconid = pmtext.iconid)") . "
            WHERE pm.userid=" . $vbulletin->userinfo['userid'] . " AND pm.folderid=" . $vbulletin->GPC['folderid'] . " " . ($_GET['unreadonly'] ? "AND messageread = 0" : "") . " 
            ORDER BY pmtext.dateline DESC
            LIMIT $startat, " . $vbulletin->GPC['perpage'] . "
        "); 


Now visit your private messages as: http://forumurl/private.php?unreadonly=1. You can put that link to anywhere you wish.