[bobds]

http://www.openwebanalytics.com/

http://piwik.org/

You will definitely need to do some customization with these. Also whatever you use, consider that most analytics GUIs are written under the assumption that very few people will have access to them. This will affect both security and performance. Your best bet is using one of the above for the backend and making an optimized stats viewing interface for your users.

[threebutton]

Great! I found piwik.org but not the other. I'll look into it. God point about performance. I'll keep that in mind and use caching or something. Thanks!