I don't know if Kitfox ever sold rib tail repair parts like this, but Avid aircraft did. I've built a bunch of these myself, it's not to difficult. Kitfox ribs are just slightly different, but not by much. I'm sure you could do the same. I glued the wood together with T-88 epoxy, and used a small brad nailer to hold them together while the glue set. JImChuk
PS just reread your post, and you mention different Kitfox 2 hinges. Kitfox 1 - 3 are all the same. Did you mean Kitfox 4? They are different and probably wont work without a bunch of other modifications