Django provides flatpages but these won't inherit from your page templated pages, only the Django templating language one. Talflatpages is a very simple app that copies completely from flatpages, but changes the default template to be a tal one, using main_template in a macro (I'm sure you can change this to suit your site).
Only a small project so not bothering with a release, grab it from SVN here:
http://svn.clearwind.ca/public/django/talflatpages/
Update: got the URL for SVN wrong, corrected.