There it is, in the public announcement at WWDC: "Xsan built in." Sure, it was small type on a list of many features, but it was there.
I'll post more info if available (outside of NDA of course).
What do you think of that 97% price drop?
Update: From the updated What's new in Lion page:
Built into Lion
The Xsan file system is built into OS X Lion, allowing any Mac with appropriate connectivity to access an Xsan volume.
Case insensitivity option
For improved performance and simplicity, you can now create case-insensitive Xsan volumes. These volumes act like traditional HFS+ volumes and do not distinguish between uppercase and lowercase characters in filenames.
New preference pane
A new Xsan pane in System Preferences makes it easier to manage, mount, and unmount Xsan volumes.
Lion supports the Asymmetric Logical Unit Access (ALUA) standard for multipathing and failover. This allows Xsan to be used with a variety of Fibre Channel RAID storage arrays.