There's a new whitepaper showing a real-world implementation of SharePoint containing approximately 50 million content items.
| This white paper presents the key decision points, architecture design and definition, and test criteria and results from a scalability and performance test conducted at the Microsoft Partner Solutions Center (MPSC) in Redmond, Washington. It is intended to provide strategic information about designing a high-volume, high-availability enterprise solution that can easily grow. |
You can get the white paper here in 3 different formats.