The VAT has two kinds of complexity: who is exempt, and what? Microbusinesses (who?), and medicine (what?), for instance? Lots of countries have handled these issues, with less furor than with the income tax. (Rates are just a variation on exemption — “what” should bear a low rate instead of no tax?)
The New York Times is up for it: “Mr. Obama would be wise to instruct the Treasury Department to start work on tax reform now, exploring carbon taxes, both to raise revenue and to protect the environment; a value-added tax, coupled with provisions to protect lower-income taxpayers from higher prices, to tax consumption and encourage saving; and a financial transactions tax, to ensure that the financial sector, whose profits have substantially outpaced those of nonfinancial corporations, pay a fair share.”http://www.nytimes.com/2012/12/30/opinion/sunday/why-the-economy-needs-tax-reform.html?hp