A number of years ago I had the opportunity to purchase a Cosmos microlight 2 place trike with a L'Mouette 21m^2 wing. The design was simple but lacking in a number of ways, one of which it was constructed from metric tubing since it came from France. But it was ALOT of fun.
At some point, I wound up selling it, but before I did, I took down all the major dimensions. Later, I sketched a foundation for the new design on paper (long before CAD) and built the frame from miscellaneous aircraft tubing, mainly from scrap from hang glider repairs at a shop I worked at. Early in the 90's, I purchased nearly everything I thought I would need from LEAF, back when they sold actual parts, before they became ROTAX whores. Actually, I got most of the parts from California Power Systems.