I'm not saying that I think the idea of an 80 foot yacht on the lake is a good idea, however as far as the launching / removal question is concerned a commercial crane and rigging contractor could certainly handle that portion of the work. Not inexpensive and somewhat challenging logistically but very possible. All those contractor barges had to get launched somehow. I seem to remember seeing some pictures of a crane lifting the Kitty Belle out for hull repairs at Fay's a couple of years ago. Nothing is impossible, it just takes more time and money!