Got a message from Benjy from the Wooden Widget folks (who designs and provides plans for the Origami Dinghy)… they have a "sail conversion" (no longer available) plan/instruction set available now.

(picture borrowed from Wooden Widget)

This is a slick modification to allow the mounting of an Optimist sail and rudder along with home made mast step and lee board assemblies. This requires amazingly little modification to the standard Origami dinghy (either 6′ or 8′ variants). Check out the videos at Wooden Widget. The plans are only <span style="font-size: 16px; line-height: 19px;">£5  (about \$10 U.S.). You still have to buy the sail and rudder (available from Xtremity). Otherwise I suppose you could find another source for similar parts and/or fabricate your own, but this looks to be an easy way to get what you need from an established supplier. Not being a sailor, I can’t attest at all the the functionality or feasibility of this, but it looks reasonable and might be a good answer to those looking for a sail rig. I especially like how it doesn’t really affect the dinghy if you wanted to remove the sail and go back to rowing… quick and easy to convert.