Looking for collaboration / content management system? ~10k users

I'm working with a non-profit community-type organisation of around 10k NZ members.Organisation structure is like:National body > District body > Local body > ClubI'm looking for a (preferably SaaS) solution to implement the following features with access control based on the above;

Document / File Repositories

Video Sharing (Training material etc)

Shared calendars

Email / archiving for the secretary of each club

Wiki

Currently looking into:

Google Apps

Microsoft Sharepoint

Don't really want all 10k users to have to sign up for a Gmail account or similar to access the systemIdeas?