I have just published an article about eZ publish 3.8 clustering in the articles section on ez.no. If you are interested in scaling eZ publish then this article should be of interest to you.
I am having a couple of talks at the eZ publish conference. This year I mostly have talks related to performance, much based on the work done lately to scale eZ publish. If you are interested in making eZ publish fast this should be of interest to you.