I've often thought along these lines - something like "your tax rate is a function of your wealth percentile" coupled with all income being taxable and provisions to avoid "hiding" income (e.g., you can't say "this income went to this company, not to me.")
A simple example would be something like, "Income tax rate is your wealth percentile squared." So if you were in the top 1% (99th percentile), your tax rate would be 98%, but if you were in the 50th percentile, your tax rate would be 25%.
This would essentially prevent concentration of wealth into the hands of a few, because at some point the diminishing returns mean the uber-rich wouldn't have any income left with which to purchase new property.
Note the de-coupling here: the tax is on income but the tax rate is based on wealth. So if you basically own nothing but suddenly make $1M, you pay very little tax. Then the next year, say, you have zero income but have that $1M in the bank (as wealth). You pay zero tax - your tax rate would be higher (due to having $1M assets) but zero income.
This mechanism would be simple (aside from trying to address the attribution of wealth to particular individuals and defining income. Easy, right?) and would "naturally" (as naturally as you can get with only force of law) address the pesky wealth distribution issue. It would also appeal to those who want to get rid of estate taxes; you would be free to live off your estate, tax free, so long as you had no additional income. But as soon as you generate income, it's taxed based on the size of the estate.
There would also need to be some reconsideration of municipal taxes which are currently property-value based; those might be better instead changed to actually be a per-capita tax since most municipal costs (education, police, fire, roads) scale with population, not with property value.