I sailed an ultralight double-paddle canoe (an undecked kayak) for a while. There is a sailing canoe forum on Yahoo which has a lot of good ideas on it. There were several famous decked canoe (kayak) cruisers in the past. Read about Macgregor in his Rob Roy canoes and Fenger in Yakaboo.
I used a BSD rig in my canoe. The leeboard attached to the thwart with the partners on it. I thought it would be unbalanced but it wasn't. The rudder was a modest aluminum kickup controlled by lines. The mast was unstayed aluminum sections, also fine. Small rigs are proportionately stronger than big ones, and have less need for stays.
I cartopped mine from NY to FL and daysailed in different places every day while staying in a cheap motel. It was a great vacation. Sailed and paddled with egrets, herons, pelicans, loons, dolphin and alligators (!).