I was recently shown Matterhorn, but it is a big beast of Enterprise Java, which often does not do very well in Free Software circles, as it is just too heavy and too hard to understand.
I'll be impressed if Matterhorn gets an active user community. It seems quite overwhelming and over engineered. Instead of having a lean, understandable core with plugins, it seems to be a everything-and-the-kitchensink solution.
Typical for a project designed and supported jointly by Universities. They have put so much money into it that it's being developed like a proprietary system, only licensed as free software.
However, we're many working on the same problems, so communication etc would be nice.