Methinks you are right on the mark.
Didn't Novak refer to his other source as someone who was not highly partisan? That would certainly fit Powell to a tee. The Dems love the guy and that is why they are not probing in his direction. Same goes for our Marxist State Department.
I disagree: The DEMS do not love Colin Powell: They've always sought to "use" him, however.
Miller's non-disclosed source is not necessarily Novak's "gunslinger". Powell could have talked to Novak, and Plame could have leaked her own identity to Miller.
Again, tho', my own thinking has me seeing beyond Powell, and more of an incestuous "indwelling" between pro-dem-CIA partisans and those who uphold themselves as "non-partisan".
Around the time the "leak" story broke, there were numerous "former" high mucka military doing plenty of ANTI-BUSH, ANTI-WOT bashing in print and via other media.
I haven't heard or even begun to look into "leak sources" like Al Jazeera as the prime leakers, yet. Thus far, the investigation has only focused on THE US. Miller is in jail. We've long since known of the "comrade in arms" relationship between the Liberal MSM (domestically) and the BBC, and other MSM in other countries.
Karl Rove says he heard it (plame stuff) from journalistic sources. "Journalistic sources" is pretty broad...