It's time to look beyond the politically dead Bush & Cheney for the GOP's options for a soft landing.
Is there any doubt that Bush & Cheney told Fitzgerald things about disclosing classified information that we now know are not true? Their best defense is that they automatically declassified the material by disclosing it, which does not change the fact of the lie, and that they were not under oath, and so cannot be convicted of perjury. Felony obstruction of justice convictions can be stopped only by suborning Fitzgerald (unlikely) or getting pardons.
Legally, that may be helpful to them, but it's still poison to the Republican party. Sooner or later, the party's backers are going to explain the facts of life to the duo. If they resign, they can cut a deal; if they fight to the death, the Democrats will run the board simply by pasting Bush & Cheney's face on every GOP poster in America.
If Cheney resigns, Bush can pardon him and appoint a successor who Bush would hope, to use Gerald Ford's excuse, would ultimately pardon Bush for the good of the nation. But who might get through the Senate?
A Senator is the obvious choice; they all know each other and there's a certain amount of collegiality. But the pick would have an enormous advantage in the presidential race of '08, and so would be opposed by his rivals. Frist would block McCain; McCain would block Frist.
Also, the GOP's backroom boys don't want to give away any Senate seats since they'll need all they can get after the tsunami of voter anger this November.
The obvious candidate is Jim Jeffords: http://jeffords.senate.gov/
Jeffords has no presidential ambitions, and no following in either party. He's not part of the Republican majority, so he's no loss to the GOP machine. And the Democrats would have a hard time opposing him because he's the one man in recent memory who resigned from the GOP on grounds of principle.
Jeffords, as a man of principle and of experience, would be a good choice for America, and that may be his only weakness. President Jeffords might be reluctant to pardon Bush; that makes him Bush's most unlikely nominee.