damned has sent out an email with a survey to anyone who has GM'd at an FG Con before and who has mentioned they will in the future.
I don't know how much use having a role call will be at this point - we've had plenty of people promise to run games in the past and then they didn't.
We'll have the FG Con website ready for GMs to enter their bookings next month and this should be the best role call we have - being able to see what games GMs have agreed to run by looking at the events they have entered on the site.