What about a summer scenario ran on Saturday nights EST? I don't know about most people in here, but my summer Saturdays are filled until dark. If they are not, I will fill them with something that is not video games (weather allowing).
Granted it is not June, but last night we had around 70 players for Fortress Europe test. This was not what you would call heavily advertised, just some words put in FSO squads' ears. In fact, many from the MA decided to land their 5.0 ENY birds and chase bombers (in order to kill or protect) for an hour or two. I think a scenario around the same time could produce high numbers, plus no one would have to concede a summer Saturday afternoon. Just a thought.