: When I was in college we got some publications from the American Plywood
: Association that had the structural properties for building products made
: from plywood. You can check the Publications page at their site to see if
: it contains the info you care about Site HTTP://www.APAWOOD.org

Sorry to burst the APA bubble but their publications won't get you anywhere close to what you need. I've got pretty much all of them in my office and, while excellent for a structural engineer or architect, for this application they're bunk.

Of course, I don't have much helpful to add either. From what I've heard and read, okoume is about as light as you'll get, esp if you opt for 3mm. If durability and rot are truly of no consequence to you, skip all interior epoxy and glass other than the cockpit. Where you do glass, go with minimalist 3.2oz satin weave and be very careful about the amount of epoxy you use to fill the weave (on the outside, don't fill it inside). Don't put in hatches (be sure to provide breather holes for the ends) and keep the end pours to a minimum.

Good luck.

BTW, I think that some folks here (other than me) are curious about your motivations. Care to share them?