A few sites:

http://mind.dreamhost.com/kayak/
http://www.pouchboats.com/building/html
http://home.t-online.de/home/derpoly/basteltips.htm#oben
http://www.rtpnet.org/robroy/baidarka/slideshow/node-o99.html#TEXT
http://www.guillemot.kayaks.com/Building/FlexibleBaidarka/index.htm
http://zaphod.iar.nrc.ca/~mbastian/kayak.html
http://www.brunel.ac.uk/~acsrrm/kayak/
http://home.pacifier.com/~qayaq/

Ralph C. Hoehn of Pouch Boats described to me the skinning process as a tough one. He recommends the use of staples.
Covering a canvas with liquid hypalon is, Peter Chopelas says, another tough process.
Some professional wielders are used to do a great job on pvc. One of them is absurdly cheap but is in Europe.
May be it would ne handy to make a first skin with thinner peeveessee, to get the skill.
Many builders use truck tarp, which probably has a much better glide than material.
I am going to try this, for better or worse.