We already HAVE a "super tax" on high incomes.

A high-income earner in Ontario already pays 5 separate income taxes (6 if you count EI which is really a tax) resulting in a tax rate in excess of 50%.  That means that the government is already getting more of the next dollar they earn than the individual gets to keep for themselves.

Anything much higher is all but guaranteed to REDUCE government income rather than increase it.  You can only tax so much before people start to move, reduce working hours or just plain old retire.

If you look at Canadian tax rates in an international perspective our highest tax rates are among the highest in the world while our tax rates on low and mid income earners are well below the middle of the pack.