Old thread, but I finally put my money where my mouth is. I said the perfect watercraft is a sailing canoe or kayak. As a very low priority project, I rigged up a sailing canoe using a 17 ft Wenonah Spirit II hull and a Balogh Sail Designs sail kit. Rigging up the sail rig was easy (one weekend) using the kit. Steering gear was another matter as there was no great kit and canoe sterns are not easy to attach rudders to. But I reinforced the stern with fiberglass pads, drilled through the hull and pads and installed canoe rudder fittings (pintles and gudgeons) from Duckworks Boat Builders Supply. Painted the stern with color matched gelcoat.
I finished this last Christmas, but only got it on the water yesterday. Didn't get a picture of the whole boat fully rigged with the sail up, but you get the idea. This is on Roosevelt Lake, which is between some nearby mountain ranges such as the Sierra Anchas.
It was a hoot to sail this thing. Canoes are pretty twisty, so everything flexes. Doesn't "point" towards the wind super well. We typically paddled to turn through the wind (tack) as the hull is too light to use momentum alone. Top speed was 5.9 mph on the first outing.
It was a warm day, around 105 F when we were out. But it was pleasant on the water away from the shore.