I'm a little late reporting this, but the Sakai community has released the long-awaited 1.0 version of its Open Academic Environment platform (formerly known as Sakai 3). Here's an overview:
As you'll see, it takes a very different approach from conventional LMSs. It doesn't yet have some of the core features of an LMS either (e.g., grade book and test engine), but it clearly is useful today for certain kinds of academic collaboration needs and represents a promising direction. When you throw this in the mix with the new commercial entrants that Phil Hill blogged about recently, it adds up to really interesting times ahead in the LMS space.