Louisiana is certainly winnable for any Democrat (well... maybe not Dean...)
Something to note from the 2000 result is this: Gore did a LOT worse in the Cajun part of the state than is normal for a Democrat.
I've once seen it put that La. actually has a three party system: There are Republicans, there are Democrats, and there are Cajuns. You need to carry two of these groups to win.
The Democrats have a chance of winning La, even with Kerry, but while larger than in the average Southern state it is still a very small chance. I have it as lean rep in my predictions.