This is really bad.
Frist thing, we need the logs. Can either of you please try three flavours of boot configuration (DisplayLink only, DVI+ DisplayLink, no external) in succession and then collect the logs with
http://www.displaylink.com/support/ticket.php?id=269
Can you also try to disable graphics auto switching? I'm not sure it could help but worth trying.
To boot disabling all third party drivers (including DisplayLink ones) you can hold shift at boot time.