Have you looked into Conform'ables? They're fairly expensive, about $100, but you can get them in varying thicknesses, too. I'm getting a shimmed one to bring me "even" in my running shoes.

I imagine your Sidis weren't cheap though, so getting them to work beats starting all over. I've avoided them because they are legendarily "tight" shoes. I can't think of anything known to run more narrow. Specialized's BG shoes I believe are shaped to be a little more in tune with the length of the foot they're fitting, but if you're a skinny 8.5 chances are you'd have the same issue. My fat feet are only happy in Northwaves and my matching tatas get smooshed into Moving Comfort "Phoebe" bras.