Thanks to some data that SurveyUSA was willing to provide me, I took a stab in this new post at 538. The conclusions are certainly not ironclad, but maybe they constitute a baby step.
There are those (Fighting Ed Garvey, for one) who suggest that Democrats who run against Scott Walker in the recall shouldn't raise money, but make an issue of how much money Walker has and where it's coming from. (How he/she would communicate that to voters isn't entirely clear,)
Those are often the same people who claim TV advertising is overrated, and that negative commercials don't work. We know Walker will have millions more than the Dem candidate, and will undoubtedly run negatives against whoever it is.
Can a Democrat beat Walker by being passive? Can pigs fly?
Maybe what happened to Newt Gingrich in Florida could be instructive. Politico reports:
NEGATIVE ADS OBVIOUSLY PLAYED A ROLE TOO - AN EYE-POPPING STAT: 92% of the ads in Florida during the final week of the campaign were negative. "Of all the spots that ran in Florida for the last week, 68 percent were attacks on Mr. Gingrich, Kantar Media found. Only 9 percent were favorable toward him. Ads assailing Mr. Romney accounted for 23 percent of the political commercials that were broadcast. Yet less than 0.1 percent were pro-Romney , Kantar found. That sliver of a figure was because of one ad the Romney campaign broadcast in Spanish, which featured Mr. Romney's son praising his father's leadership abilities."
More detail in NY Times.
Also, this from John Sides at The Monkey Cage, who also produced the graph: