import development version of treebeard from https://github.com/tabo/django-treebeard
patch treebeard to support inserting existing (but not-already-in-the-database) model instances into the tree
fix core/models.py so that we don't dig around in the content_types db table before it's been created (e.g. on initial syncdb)
apparently initial_data is a bad idea (because syncdb and migrate will clobber any updates to it). Use a data migration instead.
Migrate the page model to treebeard
patch treebeard to correctly handle multi-table inheritance (so that e.g. if you call node.get_children() it won't only look for children of the same subclass)
remove page parent relation, now that it's superseded by treebeard