I was thinking of doing the same thing. The way I plan to tackle it is basically to build a ply canoe then put a skin deck on it, rather than put just a ply bottom on a frame, since a ply boat is easy to make from scratch. I am looking at Rushton's Wee Lassie which has pretty lines and a reputation for good handling. As I am 190 lb I will probably increase the length by a foot, and reduce the height by leaving off the top strake and halving the width of the next strake leaving about 4 or 5 inches freeboard.

this approach might make things easier for your project.