Boat trailer; http://www.instructables.com/id/Tow-a-Boat-with-a-Bike/
Mineo's thread, http://motorbicycling.com/showthread.php?t=39657
got me thinking a pusher/boat that has paddles on the powered wheels for road and water propulsion. The boat would have a stand and operate the boat. throttle, rudder and engine would be controlled as if on the road.
Man, I gotta build that work shop! This could be cool.