Imagine a world where combined C-suite salaries were capped at the tax burden a company owes past a certain point. I think that would be incredibly funny to see the conflict of interest at play. Want your accounting/legal department to research tax loopholes to exploit? Sure thing, but it's coming straight out of your paycheck!
Oh, you "had a bad year"? Probably shouldn't be taking home a hundred million dollars then.
Combined with a "top pay can't make more than x times the salary of the lowest paid employee" with the exception being the tax thing, I could see it being a great double bind into making companies either pay their workers more or actually pay their share in taxes.
I know it would basically never happen in the US but a girl can dream