I got the idea of using a bullhorn bar after seeing Judi Soule's bike on the tour. This is her setup.
Turns out that my components won't fit on this diameter bar, and no matter how many places I searched and how persistent I was, I couldn't find a handlebar the right diameter. Enter consultation with machinists and my husband was able to grind out the center diameter of my components to fit the new handlebar. This is the current setup - just put in place to figure out if this riding position was really going to be better for me.
This puts my hands at no more than shoulder width apart, gives me a neutral wrist position, and doesn't put stress on my elbows or shoulders. I haven't been able to ride very far this way because of weather, but it feels very natural and comfortable. Because of the shape of the shifters I can't get the components in the very best positions - we'll solve that problem by using bar-end shifters mounted on Paul Thumbies. That combination should give me almost unlimited possiblities for shifter and brake positions. It will also be a lot cheaper and easier than starting over with a new bike.
Pictures of the final configuration as soon as the parts come in.