That is really a bummer. My wife recently has developed the same problem and I feel really frustrated as there's nothing I can do to help her. Seeing her struggles with it really makes me appreciate what you are dealing with. After some serious internet research on the subject she is now using a tennis ball to roll her foot over in a back and forth motion so as to stretch the tendon. Believe it or not, of all the things she's tried that has worked the best for her. In fact we walked a lot tonite at a greehouse after she put in a 10 hour day at work and she walked normally all night. But when she got home she put the ball under her foot in the kitchen for about ten minutes again as she said she could feel it tightening up a bit. If you've not heard about the ball method of stretching the tendon I just wanted to share.

Finish your Kitfox any way you can. You are so close. Even if you can only work on it in short bursts because of your foot, it will probably be better for your well being to have a project (challenge) in front of you than if you give it up now only to realize you need something to keep you motivated to keep moving. And if Lowell is willing to help find a way to get it done with you, that would not only be the most cost effective solution for you, but it might also be tbe most fun for you working together (Lowell's a great guy that will be fun to work with). I had the time of my life helping a friend complete his airplane. It was way more fun working together. And while I think the old Ercoupes are cool airplanes, you're gonna like your Kitfox a lot more.

One last note....stop working so hard with your business. Life is short. Let that foot have a little time off.