Theologians who have some interest in medieval exegesis likely turn to Henri de Lubac's work first and foremost. Other important twentieth century scholars like Beryl Smalley may also feature prominently. These names stand apart, like Peter Brown for late antiquity or Heiko Oberman for the late medieval period. They stand apart for theologians in particular, perhaps, because these are the scholars who have made some important headway for theological work, whether it's bringing certain figures or schools of thought to the academy's attention or articulating a narrative of historical ascent or decline that is important to our framing of the tradition. Often, however, theological work fails to adequately keep up with historical research. One can get the impression that de Lubac said all there was to say on the matter, and projects of theological interpretation can simply go on from there as if nothing else is being written apart from their own constructive work.
Another name that should be added to the short list of prominent scholars of the history of exegesis is Gilbert Dahan. Dahan is probably best known for his work on Jewish intellectual history and Jewish-Christian polemic- I believe his only book so far translated into English is Christian Polemic against the Jews in the Middle Ages (Notre Dame, 1998). Dahan's 1999 L'Exégèse chrétienne de la Bible en Occident médiéval, however, is an important work for those concerned with Christian exegesis of Scriptures. When discussing the new history of exegesis examination at the University of Chicago with Prof. James Robinson this past autumn, it was the first book that he pulled off his shelf as an important one for reading lists (although it is already ten years from publication and being superseded by further studies). Dahan has recently returned to an extensive synthetic look at the landscape of medieval biblical exegesis in Lire la Bible au Moyen-Age: Essais d'herméneutique médiévale (Droz, 2009).