Brian, Julianna,
We used DOMPDF to generate PDF’s from wp-content/themes/themename/tribe-events/tickets/email.php. We wrote a class that saved the PDF’s on the server and included the links in the ticket email. Our customization did brake the updatability of the website but our website only has to run for a month. We hacked into core files in order to generate a barcode image for the tickets by modifying the ticket-security number.