I'm thinking maybe the sonic bath option wouldn't work for dogs...at least not small dogs. I've seen my dad have one of those done...you have to have a mild epidural block done before hand and he always ends up bruised from it.
But it does seem like
something could be done...I would worry that they would break apart and cause blockage.
Stones can easily be the result of a diet too high in calcium w/out adequate amounts of Vitamin D in the diet, among other things. I would think the first line of defense for this little guy would be to determine what is causing them and go from there.