Not so sure this would have the effect intended. It's a good conversation to have, and this would probably work in some small scale. But, perhaps not for the majority.
Most information from
http://www.manta.com/mbOf the 29 million companies in the US, roughly half are privately held. This means that the CEO is usually also the owner. Or, even if s/he's not called the CEO, s/he acts in that capacity. For these companies, CEO "pay" is not really a salary. The CEO gets all the money that is left over after taxes, payroll, etc. Realistically, a smart CEO will leave some of the net revenue in the company, for growth and safety. But, that's his choice. Technically speaking, the net revenue for a year is all his, whether he chooses to take it or not.
So, if a CEO right now is used to taking $4 million out of net revenue as his "salary", out of a gross revenue of $100 million, what happens when you raise taxes? Well, theoretically, there would be less net revenue left. Perhaps less than the customary $4 million he's used to. Let's say, per the example in the OP, that his $4 million is 100 times the salary of an average worker (who gets $40,000). He'll be paying 8%, which takes $8 million from gross revenue. The incentive is to move him to 25x, which means he's only going to make $1 million, and in return pay only 7% in taxes, or $7 million.
This is why this won't work. You want the CEO to take a $3 million cut in pay, in order to save $1 million in net revenue? It's not going to happen.
(I think I did the math right. Please check me, though.)