I called up Melanie Sloan, a former federal prosecutor and the Executive Director of Citizens for Responsibility and Ethics in Washington. Her group filed a IRS complaint against ATR back in March.
The answer, it turns out, is no. The worst that could happen to Norquist, according to Sloan, would be for the IRS to crack down on ATR. His group would lose its 501(c)3 status. That would result in hefty fines, and his donors would be mighty upset, since their contributions would suddenly become taxable. One of the pillars of the modern conservative movement would be disgraced. Pretty bad. But there's not really a criminal case to make against Norquist. No jail time.
The same, it seems, would go for Ralph Reed, who's been publicly and indisputably exposed as a calculating hypocrite. But that might be his only penalty. If so, he's really on trial right now down in Georgia, where he's running for lieutenant governor.
Update: See my follow-up on this here.