My thought has also recently been to open up the boat types to include other boats than just a set type(s) of catamarans and the conversations I've had in the past was that organizers didn't want to have around the clock finish line teams and manage the logistics of when to be at which stop. I certainly understand that. However, most of these adventure races are honor system - you sign a log book when you arrive and you leave whenever you want. Just pound a stake in the sand with a log book in a box - maybe go so far as put a reflector on it to make it a little easier to find at night and if you REALLY want to be detailed and rule minded, setup a motion camera that time stamps :-).

That said, logistically, I'm not sure how you would approach a modified race format that marries the Water Tribe style races and a structured race like the Florida 300...there are technicalities like permits from local municipalities to allow beach use, deals to work out with hotels...how would the teams plan their trips and their overnight lodging where you can't legally tent camp and the only reasonable options are hotels? The lack of race structure could be an issue on what is a very structured coastline...which is probably a part of the reason that the adventure style races happen across pretty unstructured wilderness.