The University of Huddersfield is making publicly available the metadata about the circulation of its books — 3 million transactions — over the past thirteen years. This includes a book's ISBN, number of times it's been checked out, by which academic department. (It does not include information about individual borrowers.)
BTW, the library used LibraryThing's ISBN lookup service to derive some of the ISBNs, and it includes "FRBR-ish" data, i.e., other books that may be closely related.
(Thanks to Seb Schmoller's post for the tip.)