There have been a few meetups that kind of half worked at various points, though most of those were staff meeting other staff when otherwise on holiday/on a day out, mind you none of that was recent. Likewise if people are already going to a conference/concert/exhibition then something similar has been known to happen. Also going by previous threads there are quite a few around here that would not be caught dead at a computer games conference.
Hosting a full con.... I would be hesitant to even have a table/talk at one, especially not in 2014 when there is next to nothing to show. About the only thing I might consider is an overview of ROM hacking and homebrew at a hacker conference, even then I would probably go more for a quick talk type approach.