This guy converted a Mad River royalex canoe to an outrigger and sailed/rowed/paddled the inside passage from Alaska to Seattle. http://www.mit.edu/people/robot/alaska/alaska.html.
A tandem river style canoe like the Mad Rivers, daggers, Old Towne etc. might be a good starting point and used ones wouldn't set you back too much if you didn't like it. The river type epxedtion/tripping canoes have more rocker in them than the flat water boats, which also works out well for sailing.
Just remember that paddling and rowing and sailing and motoring all require different aspects of hull design. To get good results from one or two requires compromise of other design parameters. Slapping outriggers on a canoe can help meld those compromises very well.