I believe these commentaries would be great additions from Ben Witherington III:
Letters and Homilies for Hellenized Christians, Volume 1: A Socio-Rhetorical Commentary on Titus, 1-2 Timothy and 1-3 John
(http://www.ivpress.com/cgi-ivpress/book.pl/code=2931)
Letters and Homilies for Hellenized Christians, Volume 2: A Socio-Rhetorical Commentary on 1-2 Peter
(http://www.ivpress.com/cgi-ivpress/book.pl/code=2933)
Letters and Homilies for Jewish Christians: A Socio-Rhetorical Commentary on Hebrews, James and Jude
(http://www.ivpress.com/cgi-ivpress/book.pl/code=2932)
Another book that I'd recommend from Witherington is:
Making a Meal of It: Rethinking the Theology of the Lord's Supper
(http://www.baylorpress.com/Book/50/Making_a_Meal_of_It.html)