For a greenfield app, would you recommend starting with 1.7, or do you think it will be simple enough to convert from South that it's not worth it? (I have no idea how stable 1.7 is)
Andrew has said in the past that his intent is to provide a migration path from classic South to "South 2.0" which will backport migrations to earlier versions of Django (versions 1.4-1.6, I believe) and also build on top of the migration infrastructure in Django 1.7.