Ooh those are nice, i love the Cheyanne and Blackhawk, nice looking helicopters and definately before their time, the Lockheed design was a complex beast and unfortunately fell foul of the companies woes at that time but im sure had it entered service it would stil be flying today. The Blackhawk iv always thought of as a sortv delicate Hind, Iran expressed an interest before the type was cancelled (in hindsight maybe the H.60 family was the better option tho for this one?)
Your float hulled Osprey really cries out for someone to make in plastic, some styrene for a keel and side walls and Milliput for the planing bottom should just bout do the main part of it (def easier then trying to splice a Canadair hull or similar!) :)
cheers, Joe