Scruffie Marine is an Australian company with some neat designs, geared mostly around their "slotted plywood" kits. They provide the frame pieces all cut from marine plywood, ready to slide together. Self aligning and well engineered. The kits include everything you need except glue, or if you like, they will build it for you.
Looks pretty nice (although I really wish they didn’t discriminate against the Firefox web browser :-).