Hi Dan,
Are you sure you want a float plane? A sea plane is much more at home in the water. Our club members fly off the water a lot. We have several float flies each year. I myself have three seaplanes and one float plane. On a windy day the seaplanes are over the water having all the fun while the float planes sit on the beach. If you still want a float plane I would suggeat this for your first float plane. Get a set of cheap plastic floats (like the 33" Gee Bee floats sold in tower $40.00) and put them on your trainer. Fly it for one season to get the hang of flying off water. If you still want to build a scale job then the Beaver would be a good choice. If you would like to try a seaplane you can't do better than the Seamaster 40 distributed (and sold by) Ace Hobby Distributing.
Rixter