Our Barns.
Looks like fun,, and hat's off. A word of caution: When you do this kind of modification, you are drastically changing the center of gravity upwards. Or is it the point of balance?
There was a big capsize at Tobermory a couple years ago. Seems an old fishing boat had been modified several times over several years incrimentally,, and lo-and behold,, it capsized with several drowning.
A pontoon boat does seem to be a pretty good fit for this sort of thing. This is sort of what I was thinking of:
http://www.youtube.com/watch?v=s4gsgKfO6R4