Pathways
Designed as an interoperability layer on top of several different repositories.
Mentioned on https://wiki.dlib.indiana.edu/display/INF/Repository+Interoperability, which links to the (at that time) official page on http://www.infosci.cornell.edu/pathways/, which appears to be gone.
More information can be found here: http://msc.mellon.org/Meetings/Interop/FinalReport (report, pdf) and http://msc.mellon.org/Meetings/Interop/lagoze_data_model.pdf (presentation, pdf).
The project appears to be dead.