To update my earlier post, the EAC “Election Day Survey” jurisdiction-level data is available, though not terribly easy to find (and it is available in html tables!). If you navigate to the following link, you will find the State Data Tables. Then if you navigate to specific states, you can obtain the jurisdiction-level data. Perhaps at some point someone will move this data into a more user-friendly format for analysis, and if so, we’ll let you know where that data resides.
Update (September 29, 2005; 1:45pm): Excel spreadsheet links are available for these data.