Also, consider the AMT for incomes above a certain threshold (250k I think). This eliminates a number of deductions.
As a rule of thumb, someone earning in excess of 500K (exclusive of sales taxes) will pay between 40-44% of their income in direct taxes.
AMT’s maximum rate is only 28%, though. It is calculated with fewer deductions, which is why it sometimes increases total tax, but for purposes of the tax rate involved, it’s actually lower than the maximum rate.
(In fact, every time a client of mine complains about AMT I remind them that it’s a lower-rate flat tax with minimal deductions. Isn’t that what they told me would fix all of our problems? 
)
Local property tax can get you to 100% of your salary (or beyond!) in a single step. My property tax is tied to the value of my land+improvements (house, etc.) as established at the time of purchase. If I had chose to buy a sufficiently expensive house, every dollar I earn in salary would have to go to property tax.
Can’t you voluntarily pay more tax than you owe, so theoretically the only limit to how much you can pay is how much you have (or can borrow).