Just brainstorming late tonight about this idea. I know it isn't anything close to being original, but what about this locking latch for the middle
And some hardware on the sides somewhat like these to keep the sides in place?
http://www.nauticexpo.com/prod/south...514-55394.html
any other ideas? Not sure how the side hardware disengages. I was looking for the kinds that you push to lock and then push again to unlock, but this one seems to have a sliding lever used to unlock the latches.