They are there, but don't usually show themselves unless some starts shouting "JP ONRY" or some random obscenities for 10 minutes(if that) in Ul'dah.

I saw one when someone was stuck in the instance for WAR AF Body quest and couldn't get out of it even after logging out multiple times.

I highly doubt that anyone has a list of GMs, and if they do, they probably can't/won't tell you.