template_loader.py

import os
from functools import partial

from django.contrib.sites.models import Site
from django.template.loaders.filesystem import Loader as FilesystemLoader


class SiteDirsLoader(FilesystemLoader):
    def get_dirs(self):
        templates_dir = super(SiteDirsLoader, self).get_dirs()[0]
        appendr = partial(os.path.join, templates_dir)

        domains = Site.objects.values_list('domain', flat=True)

        dirs = map(appendr, domains)

        return [appendr('default')] + dirs