If you are not aware of it, I would direct your attention to the Dartmouth Dante Project, which has online many commentaries on the Divine Comedy: http://dante.dartmouth.edu/search.php .  You can review the commentaries by author, text, and passage.  Thankfully, many of these commentaries are in Latin.  For instance, you might like the commentaries by Benvenuto da Imola or the third commentary by Pietro Alighieri.

The recent translation of Fr Ernest Fortin’s book on Dante has led me to think about what a strange figure Dante is, and his relation to Thomas.  I recently read an older (1977) book on Dante by Kennelm Foster called, The Two Dantes.  There is an interesting essay about “Dante and St. Thomas.”   The title essay is partially on Dante’s original invention of a Limbo for seemingly fully virtuous adult pagans, and what it means for Dante’s understanding of nature and grace.