In exploring the data discussed in my last post, I found one group that stood out: people without a college degree who received a salary. 56% of them said they were Republicans, and only 29% said they were Democrats. Other whites (ie either with a college degree or paid a wage, commission, or some other method) were almost evenly divided: 43% were Republicans and 42% were Democrats.
I'm not sure whether this would hold up in other data--the difference is statistically significant, but not so much as to remove all doubt. But it is intriguing.