I have been looking for a light weight duck hunting boat without having to take a second mortgage. Reviewing your web page I noticed some of your plans include aluminum except for your duck boat plans. An aluminum duck boat would be heavier than plywood, certainly more expensive, and aluminum tends to be noisy. Not a good attribute in a duck boat. Small aluminum production boats use thin aluminum with riveted seams which is impractical for the home builder.
Welded hulls are heavier than plywood.
Other than that, any boat that can be built in sheet plywood could be in aluminum. No specifications are available for aluminum construction. I have been looking for quite some time for a design that I would like to build. Although I have taken a boat building course at Plymouth Plantation, I have never built a boat on my own. Problem is that I don't have a decent surface to loft on.