My family and I did a cruise over Christmas a couple years ago. We invited family, told them what boat we were going to be on, and said see ya if we see ya! 17 members of my extended family came - it was a blast. We used walkie talkies to communicate on the boat so we could be in touch without hovering over each other. And then, the walkie talkies got to be so fun we all developed code names and geeked out over it. So yes, cruises with a large group can be great!
The boat can also reserve rooms for events and things if you plan in advance. I'm curious how many people would go, how many speakers and who would be good... would we raise a little money? I think it would be tremendous and am willing to take part in the planning and organizing.