Levy, Ian Christopher, trans, ed. The Letter to the Galatians. (Medieval Bible Commentary) Grand Rapids: Eerdmans, 2011. 0802822231, 9780802822239.
There are two reviews available of this book from Ian J. Elmer and Akio Ito.
Both reviews are quite positive and as this is the first book in this series it bodes well for future volumes to be useful as well.