The University of Hull had a Fedora-based institutional repository (IR) in operation some time before Hydra was conceived. For us, the project involved converting all our existing content from a Fedora 2.2.4 format to Hydra-compliant Fedora 3.4.2 in addition to implementing the Hydra technology stack itself.
Hull's content does not come from a single source. Thus Hull's implementation has to be able to cope with content coming into the repository from non-Hydra sources, although such content is Hydra compliant. In addition, the content covers a wide range of types (text, images, multimedia, databases, ...) and requires the full range of Fedora objects - simple, compound (multiple content datastreams in one object) and complex (child object(s) containing content datastreams).
These many considerations have all had their impact on the user interface (our IR Hydra head) and on its technical underpinnings. One constraint that we should be clear about is that we needed our first pass at the UI to bear a significant resemblance to that of the old repository. We did not want to give our many users a major culture shock.
Hull has been lucky over the years 2005-2011 in obtaining a number of grants from the JISC to help with work on the various systems that feed content to our institutional repository. The latest JISC funding (February - September 2011) is an eight month grant to implement Hydrangea (which of course significantly overlaps with implementing Hydra) over our repository. Some of the material on these Hull pages is the result of the JISC funding the documentation of that process to aid the wider community.
The list and links below are under continuous development.