James Fallows asks: 

1) At any point will the right-wing press join the effort to hold Palin accountable for her false claim, as all of the press held Clinton responsible?

Unless I count as part of the right-wing press, which is something of a stretch, no.

2)  If Palin keeps making the claim, will press critics redouble their debunking, as they did with Clinton, or taper off for fear of seeming biased or boring?

They will probably give up on it out of fear that they are creating the impression that the media are engaged in a purely anti-Palin campaign, which might very well be contributing to the tremendous outpouring of sympathy and enthusiasm for her. 

3) At any point will Palin herself — or, far more significant, McCain — acknowledge that there are such things as fact and fantasy, and stop making a demonstrably false claim?

Why do that when lying works so well for them?