With CrownPeak, you can structure your content and your sites any way that you'd like - and of course you can limit access to only those sites that you want your users to be able to edit.
Here are a couple of examples of customers who are using CrownPeak to manage multiple sites - some with similar look and feel - and some completely different:
LISC (Local Support Corporation)
See all of their chapter web sites.
Miller Beer
Chicago Events
Denver Events
IFAW (International Fund For Animal Welfare)
Stop The Sealhunt
Stop Whaling
.... and dozens more here