Check these out. With some help from a buddy at work I found GIMP and was able to use it to set things up along the lines I suggested here. So far I've got two maps - one of Presidential race results and another of Senatorial race results.

Here's the one for the Presidential race.

And here's the Senatorial race. Note how far I had to shift the scale into the blue to get any color variability at all for this race. (The range was 60.8% Obama at the low end (pct 47) and 76.0% Obama at the high end (pct 43)).

Always good to know where the votes are coming from. Thanks, everybody!