I came across this online doctoral dissertation on Galatians tonight, although I seem to have seen it in the past but forgot. Hop on over to download it in PDF format.
Ian Jeffrey Elmer, Paul, Jerusalem and the Judaisers: The Galatians Crisis in Its Broader Historical Context. PhD, Australian Catholic University, 2007.
Elmer tries to show that Paul’s opponents were representatives of the Jerusalem church and thus Christians. Not surprisingly he sees a connection between Acts 15 and Galatians 2 and believes that there was extreme tension and animosity between Jewish and Gentile Christians during this stage of the church.