Tax Reform Agenda for The 109th Congress summarizes alternative tax plans, including a consumption-based tax system:
However, economists know that a consumption-based tax system need not look like a VAT or a sales tax. It can appear very much like an income tax. All that is really necessary is that saving be entirely exempted from taxation. If that is the case, then all that remains is consumption. Hence, the burden of taxation will necessarily fall on consumption even though consumption is not taxed directly.
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The principal virtue of a consumption-based tax system is that it is much less burdensome to the economy than an income tax raising the same revenue. That is because saving, investment and risk-taking are especially critical to growth.