Happy Birthday to Mrs Brisket!
How bout a pig in a pit, use grillzilla for onions, peppers, tortillas etc. Everyone can build their own.
When I cook for that many people, it's easier if I have one large hunka meat (like a pig).... then I can enjoy the party and not spend time babysitting small portions.
(yes I'm lazy)..
Good luck with what ever you do Bob, I'm sure Mrs B will love it!