My colleague Constance Malpas has created an interesting Worldcat List in support of ongoing work:
Selected print-only, refereed scholarly journals in the humanities with fewer than 50 aggregate library holdings. Holdings count limited to recs containing ISSN and English-language cataloging. [RLG Prospective Journals Preservation Project - sample titles]
This is an interesting list in itself. What struck me was how nice it was to be able to publish a list so that it was publicly referenceable, the data could be shared, and the items link back to library holdings.