I am trying to sort out Rabanus Maurus intellectual connections with people from Eastern origins. Is there any updated study that might shed some light on this matter?
They are some works about Rabanus and Judaism, but I don't know if you're looking for that or if you already know. Just in case, Albert, B-S, Anti-Jewish exegesis in the Carolingian period: the commentaries on Lamentations of Hrabanus Maurus and Pascasius Radbertus, Biblical Studies in the Early Middle Ages: Proceedings of the Conference on Biblical Studies in the Early Middle Ages, Ed. Claudio LEONARDI and Giovanni ORLANDI, Firenze: SISMEL, p. 175-192; Verstrepen, J.-L., Raban Maur et le Judaïsme dans son Commentaire sur les quatre Livres des Rois, Revue Mabillon, 68 (1996), 23-55.
There are two faily new works that might interest you: 1) Philippe Depreux (dir.), Hraban Maur et son temps (CMHA, 9) Turnhout 2011; 2) Sita Steckel, Kulturen des Lehrens im Früh- und Hochmittelalter. Autorität, Wissenskonzepte und Netzwerke von Gelehrten (Norm und Struktur 39), Böhlau Verlag: Köln, Weimar, Wien 2011. Stickel particularly analyses the intellectual network of Hrabanus Maur. This book is not only very exhaustive but also one of the major works about intellectuals and learning in Carolingian times today.