would mod_wsgi + django be enough or is something else needed ?

Django is a definite must have. People are finally starting to see the value in it and its powering some of the most heavily trafficked sites on the internet today (e.g. Pinterest, Instagram, etc.). Plus, the GIS tools in Django/PostgreSQL are unrivaled in open source offerings and beat some commercial ones even.

That would be good enough to run web app/s so +1 for pyhon/django support!