ANSWER FROM SMF -
Lol, at first I thought it wasn't, but it looks like it is possible.

In Sorces/BoardIndex.php find:
$context['list_users_online'] = array();
and above it add:
$context['list_mods_online'] = array();
then find this:
$context['list_users_online'][$row['logTime'] . $row['memberName']] = empty($row['showOnline']) ? '<i>' . $link . '</i>' : $link;
And replace it with:
if($context['users_online'][$row['logTime'] . $row['memberName']]['group'] == 1 || $context['users_online'][$row['logTime'] . $row['memberName']]['group'] == 2)
$context['list_mods_online'][$row['logTime'] . $row['memberName']] = empty($row['showOnline']) ? '<i>' . $link . '</i>' : $link;
else
$context['list_users_online'][$row['logTime'] . $row['memberName']] = empty($row['showOnline']) ? '<i>' . $link . '</i>' : $link;
This is assuming that your moderartors are group 2 (first line)
Now find this:
krsort($context['users_online']);
and above it add:
ksort($context['list_mods_online']);
Finally, in BoardIndex.template.php of the default theme and/or the theme your using find:
// Assuming there ARE users online... each user in users_online has an id, username, name, group, href, and link.
if (!empty($context['users_online']))
echo '
', $txt[140], ':<br />', implode(', ', $context['list_users_online']);
and replace it with:
// Assuming there ARE users online... each user in users_online has an id, username, name, group, href, and link.
if (!empty($context['users_online']))
echo '
', $txt[140], ':<br />', implode(', ', $context['list_mods_online']), count($context['list_mods_online']) > 0 ? '<br />' : '', implode(', ', $context['list_users_online']);
thanks to Kays at SMF