Senator Ron Wyden of Oregon, a Democrat, and Senator Dan Coats of Indiana, a Republican, have introduced the Bipartisan Tax Fairness and Simplification Act of 2011.
According to their summary, "For individuals: Wyden-Coats reduces the number of individual tax brackets from the current six to three: 15 percent, 25 percent, and 35 percent and eliminates the Alternative Minimum Tax completely....Wyden-Coats also makes American companies more competitive by reducing the top corporate tax rate and replacing the existing six corporate rates and eight brackets with a single flat rate of 24 percent."
That 24% corporate rate is a percentage point lower than the 25% that Republican Paul Ryan is proposing in his "Path to Prosperity."
The Wall Street Journal has a news article about the fact that the legislation would eliminate the federal tax exemption for municipal bond interest and replace it with a tax credit of 25% of the interest earned.
A YouTube video of Senator Coats talking about the legislation is below. He says it's "revenue neutral," according to a "static" analysis that doesn't take into account any growth-generating effects.