Try as I might, I see no benefit using this route.
That's because you are not looking at the big picture.
The electorate doesn't care. The electorate is damn relieved Saddam is gone -- whether or not they suspect, in the back of their minds, that the last 18 months was always really about Saddam, not bin Laden and his merry men. The electorate is damn happy to see that we liberated Iraq from an evil dictator. The electorate will be even happier when gas prices fall below $1 a gallon in the next few months. And the electorate will be damn satisfied with the job Bush has done on the national security crisis if, as seems likely, the presidential election rolls around without any follow-up to 9/11.
The Democrats will try to make the failure to find WMD an issue. The electorate won't care -- therefore, Bush doesn't care. Further, the Dems need to be careful what they wish for, because Bush has booby-trapped the whole deal. Supposing the Democrats do get a wide-ranging investigation into what we really know about 9-11. Well, congress already tried to get the CIA to cough up, and the CIA balked. You know what the biggest thing they balked on was? Khalid Sheikh Mohammed. Can you guess why they balked on the issue of Khalid Sheikh Mohammed, and who Khalid Sheikh Mohammed worked for? The Democrats aren't going to like the answer to that, if they ever find it out. Similarly, the question of what "secret intelligence" ultimately motivated Colin Powell to wave that little vial of phony anthrax at the UN is ultimately going to lead back to the question: who sent the anthrax? And, while full disclosure on that might well be embarassing for the administration, it would make the Democrats look much, much worse. Do you see how sweet this setup is?
What about the rest of the world? Don't we need to convince them that we were on the up-and-up when we used WMD to justify attacking Iraq? Not really, provided the issue is spinnable either way -- which it will be. The less we come up with in terms of WMD, the tougher we look. In fact, if we told the real story on WMD, we actually wouldn't look very tough at all. And the question becomes, is it better to be feared or to be loved? And the answer to that question, as Machievelli pointed out in The Prince, is that it is much better to be feared than to be loved.