[QUOTE=Tuckerfan]
Here’s a slight variation on WhyNot’s idea: Taxes remain the same, but folks are allowed to contribute money to government programs which they feel are underfunded. For example, I personally think that NASA’s getting the shaft when it comes to government funding, and if it were possible, I’d happily have extra money taken out of my paycheck (or simply mail NASA a check every so often), but it’s impossible for me to do so. (Well, I could buy something from NASA’s store on their website, but quite frankly, I have enough crap as it is.) Someone else might think that HUD needs more money, and could give extra money to them. I realize that most people would probably not do this, but even if a department netted only an extra million or so a year, it could make a difference for many of them in some of the things that they do.
[/QUOTE]
I can see it now:
The NASA Phone-a-thon Fundraising Campaign! 
[QUOTE=Anomalous Reading]
Taxes are largely funded by a small sliver of the population. I don’t know about anyone else, but the gov’t hasn’t taken (and kept) much of any of my money. I’m sure that will change - especially as the kids leave, but really… the rich would have inordinate sway in what gets funded.
[/QUOTE]
Bolding mine.
This depends on one’s definition of “inordinate.” Allowing people a pro rata say in how money gets spent is “inordinate” only if one views the purpose of the tax code as, in part, the redistribution of wealth. Fortunately or unfortunately, our highly ‘progressive’ tax system does have this redistributive intent and effect (with, as you note, something like half of federal taxes being paid by 2% of the population).
Obviously, a government set up to take wealth from producers and give it to non-producers is not going to want to afford the producers much direct say in how that money is spent, as the producers would likely tend to steer their payments away from wealth redistribution (“economic stimulus rebates,” subsidized housing, socialized medicine, etc.), and the “taker” class, while they might designate their (minimal) tax payments to the redistributive programs, would never be enough to sustain the giveaway programs.