Multi-tenancy through partioning

[Brian Sanders]

Is anyone using partitioning to support multi-tenancy for a SaaS application? If so, could you please describe your set up and experience? Specifically I'm interested in hearing about:

1) Your model for tenant and user data
2) How you enforce access restrictions (i.e. each tenant only sees its own data/tables/records)
3) Your front-end and back-end process for creating new tenants and users
4) Your experience with scaling, replication, or clustering:
- How big are your database(s) and tables?
- How are you splitting the database to support large data sets?
- How are you optimizing your database for faster response times, faster search, reduced storage requirements, faster and more comprehensive reporting?
5) Your experience with BI and reporting applications:
- What are you using?
- How has integration worked with your multi-tenant model

If anyone knows any good resources, web sites, tutorials, books, etc. please post them.

Thanks!