Sidi has "Mega" shoes as someone else mentioned, which are wider, and men's shoes in general tend to be a little wider than women's. Some say Sidi's regular shoes run narrow and I've heard the same remark about Shimano's road shoes. At least in men's sizes, Diadora's shoes run on the wide side per what I've heard friend's say. I know nothing in regards to mtb shoes so no help there.

If you stick with road shoes or when you go back to road shoes (if you switch to your mtb setup for now on your road bike - which isn't a bad idea if it helps your pain) you may want to look at Speedplay's pedal system. I personally have Look's traditional Keo pedals and like them (their new "Keo 2 Max" pedals have an even larger surface area though, btw) but know that Speedplays have worked well for many people who have had some type of physical problem (knee pain, foot pain, etc.). Good luck!