http://dialnet.unirioja.es/servlet/fichero_articulo?codigo=3136587&orden=0
suggests that Spain's top 1% have a similar order of the national wealth (20%) to those in Anglo countries.
Better general ways would be:
(a) location benefit levy - a tax on land rental values which is essentially a tax on the privileged use of the land commons;
(b) a levy on gross revenues from intellectual property rights - ie a tax on privileged use of the 'creative commons' of knowledge;
(c) a limited liability levy on gross corporate revenues - limited liability is another untaxed privilege;
(d) levies on use of non-renewables - another commons - and so on.
Then I would get rid of all other taxes except levies on earned income aimed at funding education and healthcare.
There is no chance of doing this via the State, since it the privileged turkeys who manage and own the country would not enact Christmas.
But I think in the emerging networked society and economy such an architecture could well evolve. "Any economic unit can emit money. The serious problem is to get it accepted" Hyman Minsky