We appear to have a semi-official, nonbinding answer from a reliable source. IRS Criminal Investigation Division Chief Eileen Mayer appeared at the the May 9 Civil and Criminal Tax Penalties session of the American Bar Association Section of Taxation meeting in Washington, DC. Tax Notes Today, 2009 TNT 89-2, gives us the quote:
Asked about the possibility of negotiating the penalty amount on the civil side, Mayer said, “The penalty is what the penalty is. I don’t believe there is the intent to negotiate within the confines of the offshore accounts.”
Tax Notes Today is a pay service. Sorry I can’t link to the article. I get TNT through Lexis.