I learned something new yesterday. I was looking for a pair of Chaco Z/2 sandals (strap over the big toe), wide size, sticky sole (a sole that will mark up your floors but does a nice job on wet rocks, etc.). Turns out Chaco doesn't make a Z/2 pro in wide sizes.
But, when I called them, I learned they will custom make a pair - for roughly an extra 20 dollars. choose your webbing, style, sole, etc.
I'm sure this is all built on their standard footbed - you can't customize that. But, it's a nice option if you can't find the combination you want online, and not so expensive that it's prohibitive.