Earlier this year, the team working on the PHAEDRA II project (including researchers from VUB, UJI, Trilateral and GIODO) conducted interviews with representatives of (very nearly) all the European Member States data protection authorities. The aim of the interviews was to get the perspective of the authorities on the ongoing data protection reform process, better understand how they cooperate and collaborate with each other, and get some guidance on various activities planned under the PHAEDRA II project. We collated the the interviews together into a summary report.
I'm currently working on a follow-up report that collates best practices in collaboration between DPAs in a number of topic areas (tools and platforms, communication with the public, investigations, etc).
In related news, the book that collates together the presentations from the final conference of the first PHAEDRA project is now available, and can be downloaded from the project website. http://www.phaedra-project.eu/reports/
There are physical copies in existence too. Check out the classical reference in that front cover.