So long as all income is counted as income. No tax shelters, no hiding profits with losses and all the other chicanery. I think the biggest problem you will find with this idea is that the rich won't go for it. People with the income of Mr Buffet like paying less in taxes than people who make substantially less than he does.
Forget all that. Only people with above the table money would be taxed.
US National sales tax gets everybody.