yes, Unity has levels of administration currently in 2.x. COS serves two purposes, one is to enable/disable licensed features for users, but it's primary roll is to restrict access to the SA/AA/SM and dictate what objects admins can get at in the SA once they get there (i.e.levels of admin)
The model gets a bit better in 3.1 since it'll allow individual control over read, add, delete and edit rights for subscribers, COS objects and public distribution lists. Currently it's an all-or-nothing model for each object type which is a little broad.
Jeff Lindborg
Unity Product Architect/Answer Monkey
Cisco Systems
lindborg@cisco.com
http://www.AnswerMonkey.net (new page for Unity support tools and scripts)