Not quite. I see the bloc south splitting the dixie social conservative vote between economic left/right and the social moderates/liberals going to the dems. Also I don't see a new left party emerging. A party that's left on social issues but not jacobin/radical(advocating civil unions instead of gay marriage, taking a compromise position on abortion etc) and center-right on economcis owuld be more likely.
While a division of the dixie social conservative vote along economic lines is
very possible, I don't think the Dems would benefit, especially if it is the Southern Dems who turn into the Bloc Southern. They'd hold a few inner-city bits (although even there it would vary) but the bulk of the competition would be between the GOP in the suburbs and the Bloc Southern in the countryside and working-class urban areas.
That would be an interesting map, actually...
The New Left Party would be in New England, and it's already been mentioned in another thread as well (Forum Community?). It would compete from the left against New England Dems.
Now, the party you're talking about sounds more like a moderate libertarian party, and they'd be in the West Coast (and parts of the Mountain West).