For those of you looking for reads on the issue of the Kingdom of God and the Roman Empire, here are some places to start...
Desire of the Everlasting Hills: The World Before and After Jesus [Thomas Cahill]
Matthew and Empire: Initial Explorations [Warren Carter]
In Search of Paul: How Jesus' Apostle Opposed Rome's Empire with God's Kingdom [John Dominic Crossan and Jonathan L. Reed]
Jesus, Justice, and the Reign of God: A Ministry of Liberation [William R. Herzog II]
Parables as Subversive Speech: Jesus as the Pedagogue of the Oppressed [William R. Herzog II]
Jesus and Empire: The Kingdom of God and the New World Disorder [Richard A. Horsley]
The Message and the Kingdom: How Jesus and Paul Ignited a Revolution and Transformed the Ancient World [Richard A. Horsley and Neil Asher Silberman]
Paul and Empire: Religion and Power in Roman Imperial Society [Richard A. Horsley]
The Liberation of Christmas: The Infancy Narratives in Social Context [Richard A. Horsley]
Herod: King of the Jews and Friend of the Romans [Peter Richardson]
Colossians Remixed: Subverting the Empire [Brian J. Walsh and Sylvia C. Keesmaat]
The Seven Cities of the Apocalypse and Roman Culture [Roland H. Worth, Jr.]
The Seven Cities of the Apocalypse and Greco-Asian Culture [Roland H. Worth, Jr.]
The book, however, is Christ and the Caesars by Ethelbert Stauffer. Incredibly hard to find, but well worth the effort... it's a gold mine, the holy grail!