On my desk to catalog is Mark E. Powell's new book, Papal Infallibility: A Protestant Evaluation of an Ecumenical Issue. Powell is a professor of theology at Harding Graduate School of Religion, and contributed a chapter to Canonical Theism on the same topic as his present study.
Meanwhile, James T. O'Conner's The Gift of Infallibility is being offered at Ignatius Press for a special 30% off. O'Conner is probably more widely known for his study on the Eucharist, also available through Ignatius. From the publisher, "In The Gift of Infallibility, theologian James T. O’Connor clarifies the idea of infallibility. He provides a helpful translation of the “relatio” or official explanation by Bishop Gasser given at Vatican I, the Church council that defined the dogma of papal infallibility. Also included in this important volume is the first draft of chapter 4 of the Dogmatic Constitution Pastor Aeternus, as well as the final, official chapter of the constitution."