The effects of a consumer tax have been debated, and its effectiveness would be in the details.
The key for the tax would be to tax spending on items not considered basic staples. Taxing the staples would make the tax be mostly burdensome to the poor ... since they purchase mostly staples (food, clothing, shelter) as a proportion to their income.
Personally, a tax on spending and a cut in the personal taxes would have two effects on me: 1) I'd save more and 2) I'd spend more as well since I'd have 40% more money. So for example, if I pay $400K in taxes this year and suddenly I didn't have too ... I''d probably save $300K (save means to invest, stocks/partnerships/munis) and spend $100K in various consumer goods/travel/etc. So from my perspective, I would contribute to stimulating the economy under this tax plan.
Like many good ideas, getting something like this to pass in the US is unlikely.