Sorry I didn't post up sooner. I had a nerve biopsy done and no problems were found. My Podiatrist diagnosed the problem as Neuropathy. His diagnosis was validated by his partner who is a competitive cyclist. He checked my shoes (Sidi Mega wide) and the fit. He liked the width. However, he did suggest that I ditch the Speedplay pedals. The contact area is too small and the pressure is too high under the balls of the feet. (pressure = force*area). An intermediate step to solving my problem is to get stiffer wide cycling shoes. After trying on a lot of them, the only shoe I could find was, again, Sidi, the 6.6 Genius. Although they do make a Speedplay specific shoe with a reinforced cleat area - http://www.sidiamerica.com/sidi/road/genius_6_sp.html -, they have no plans to make a mega width in my size (45.5) I elected to go with the standard shoe as Speedplay makes an adapter plate. The deflection on the sole is only 1.5mm with a 100lb weight hanging from the sole. Certainly stiffer than my Sidi Genius 5 shoes (almost 5mm flex)

My Podiatrist casted my feet and had a pair of custom orthotics made. He uses them too and says I should notice a significant difference in pressure. I should receive my shoes in a couple of days and get the orthotics correctly cut to match the shoe. I also got an Rx for Metanax, a herbal medicine that claims to be able to restore nerve damage. My Podiatrist said that he finds only about 50% of the people get positive results from using it, but the Rx was a money back guarantee, so why not? Tried it for two months and no change. Money refunded.

So, at this point, I am going to give the new Sidi 6.6's and orthotics a try to see if my Neuropathy improves. If not, then the next step is to get a bigger platform pedal. That is a significant investment because I ride Speedplays on my road bike and both of us ride them on our tandem. Three sets of light pedals are expensive. If that doesn't work, then there are a lot of advancements made in treating Neuropathy and I will go down that path. Will let you know what happens.