Michael,
We "winged it" I guess. My brother and I built a 20 footer based on research and experience. Just don't underestimate the time it takes to complete a project like this. Depending on the finish you want, it can take a while...took us about 5 years. We both work full time and worked on it 2 nights a week after work...and some other times when we could squeeze it in. My brother's wife made a website to share with friends etc. We don't build or sell them....but I'd be happy to share our experiences with you. We did make our share of mistakes and I'm guessing if we do it again, we will be able to cut out at least 30% of the time...maybe more.
http://peltonbrothersmarine.com
Matt