I haven't, but I wonder if a combination of Quip and MemberPages would do it (and maybe NewsPublisher).
Users could create a new page with NewsPublisher to create the "ticket", you and the user could use Quip to communicate about the ticket, and you could use a fairly simple custom snippet or getResources to show the user links their own pages. The createdby field of the resources would be the User's ID, so the menu snippet could look something like this (the user would have to be logged in):
$userId = $modx->user->get('id');
$docs = $modx->getCollection('modResource', array('createdby' => $userId));
$output = "\n<h2>Tickets</h2>\n";
if (! empty ($docs)) {
$output = "<ul>\n";
foreach($docs as $doc) {
$pagetitle = $doc->get('pagetitle);
$url = $modx->makeUrl($doc->get('id'), "", "", "full");
$output .= "\n" . ' <li><a href"' . $url . '">' . $pagetitle . '</a>';
}
$output .= "\n</ul>\n";
} else {
return '<h3>No Tickets Found</h3>';
}