Pat, that is good to know about P. Walnut. I bought some off ebay once and liked it a lot. It was like slightly lighter ipe.
Marc and Pat, Re: glueing fibers on the back. I don't think this is the answer either, and I wouldn't do it like joachimM is suggesting, but T.Baker did it in TBB, and I have used linen cloth patches just like this before. Once to arrest a fret, and a couple times to "put wood back". It works. I have even built up low spot by applying a 1" long patch with TB III, blending it with a scraper, attaching a 2" patch, blending, and then a 3" patch, which I combed out at the edges while wet. Then, I wrapped the whole patch with glued on linen thread. Those two bows are still shooting.