How to configure server for small hosting company for django-powered flash sites?

Maybe. I don't think the built-in admin interface is really designed to corral admins into their own sites. The sites framework is more suited to publish the same content on multiple sites, not to constrain users to one site or another. You'd be better off writing your own admin interface that enforces those separations.

As far as serving content goes, it seems like you could serve up a common (static) Flash file that uses a dynamic XML file to fill in content. If you use Django to generate the XML, that would give you the dynamic content you need.

This django snippet might be what you need to keep them seperate:

http://www.djangosnippets.org/snippets/1054/

"A very simple multiple user blog model with an admin interface configured to only allow people to edit or delete entries that they have created themselves, unless they are a super user."

Depending on the amount of sites you're going to host it might be easier to write a single Django app once, with admin, and to create a separate Django project for each new site. This is simple, it works for sure AND as an added bonus you can add features to newer sites without running the risk of causing problems in older sites.

Then again, it might be handier to customize the admin such that you limit the amount of objects users can see to those on the given site itself. This is fairly easy to do, allthough you might want to use RequestSite instead of the usual Site from the sites framework as that requires separate settings for each site.

There exists this one method in the ModelAdmin which you can override to have manual control over the objects being edited.