hi Wayne;
welcome aboard! while rooting around at www.bateau.com i ran across free plans for a folding kayak. it didn't look like much, but maybe a place to start from when designing your own.
as for addictions.....interest is first stage. i've been building for less than two years and am currently working on for forth and fifth at the same time. #4 is at my shop (where i make a living). #5 is on the ceiling in the livingroom of my apartment. i'm never very far from a "fix".
best regards;
daren....