While the rich still find loopholes and tax shelters, they still pay a hefty amount of taxes in most respects. Lets make another point, that you missed, perfectly clear. Those who are rich make up a very small percentage of our population. Either way, they really don't make that big of a difference either way.
As far as corporations not being taxed and thereby dropping prices and moving more jobs back to the states, that is a fucking fairytale too. They wouldn't drop prices and they would also keep jobs overseas due to labor rates, not due to taxation. Their largest tax hit, and one of our country's biggest revenues, is from profit and the government will not give this up.
Next, one of the main reasons for an income tax over something variable, such as a sales tax, is that it is somewhat forecastable and allows for budgets to be made. How do you expect our Treasury to react to an unpredictable revenue that is not definable except by yearly sales? Not going to work.
Last the main reason that whole idea is just basically retarded is due to the aspect of our economy. You raise sales tax that much, you end up stifling spending. Our economy is built around this. The domino effect would cause that whole idea to turn around, bite us in the ass, and put the US into a depression. Also the fact that you mentioned so called proration and that we would eliminate tax on items that are essential is ludicrous too. Under the "Fair Tax", this is only going to come from luxury items? Irony. How FAIR is that?