http://en.wikipedia.org/wiki/Negative_income_tax#Flat_tax_wi...
Edited to add: It's worth noting, though, that you can't produce every possible progressive tax rate curve with this method. It's certainly possible to prefer some curve that is unattainable this way. But a simplistic "a tax flat in dollars is regressive in utility" isn't applicable.
I'm in favor of a much simplified structure, applied evenly, as fairly as possible, and much smaller government needed to operate it. A lot of spending comes down to complicated bureaucracies, reducing those is a big step. Another benefit of a basic income, is it would allow the revocation of a lot of welfare and stimulus programs, and their own layers of corruption and bureaucracy.
I'm also in favor of cutting the overall defense and operations budgets by at least 2/3 ... There's a lot of ways the federal government could be much more effective, and reduce expenditures at the same time.
And although I don't know how much I feel it is the government's place, a baseline healthcare system could even be funded in a much better way than Obamacare. I tend to lean libertarian, but I'm a pragmatist. I just want solutions that are responsible, and have a chance at making things better, while avoiding as much chance for corruption and bureaucracy as possible. Not to mention reducing the footprint of the federal government, and reducing the impact of corporate protectionism along the way.
Plus this whole issue of 'companies returning money to shareholders' is again only favoring the rich. It will be a long time before any significant portion of my income comes from dividends and capital gains. To make money in this way, you have to have a huge amount of capital invested already. Just to prove this point, if you made a very nice 10% per year before taxes on your investments, you would have to have 100,000 invested to make an extra 10,000 per year. If you are only making 50,000 per year, that would take a 20% contribution to your pre-tax retirement account for TEN years before you reached that level of invested capital. Sure, it would happen a little faster because of compounded interest and reinvested earnings, but I think my point is clear.