It is a position that many Christian scholars and thinkers have espoused over the years. I think that this link would provide a good exposition of the position I am referring to.
Basically it says that Luke's writing isn't completely trustworthy and that Paul's epistles show much innovation from Jesus' teaching. The Jerusalem Church started by Jesus, led by Peter and James, believed in salvation through following the Law, as taught by Jesus in for example in Matthew 5:17-20 and Matthew 19:16-21 . Jesus never taught that the Law would be nailed to the cross, even when speaking in the Gospels about the Son of Man being given over to be crucified and rise on the third day.
Paul's background was in a limited Greek version of Judaism, and he bases all his scriptural quotes on the Septuagint. Since he never met Jesus in real life, and did not study with his disciples, Paul relied on his own visions and went on missions to Asia to convert various people to his cause. His encounters with the Jerusalem Church (from which Nazarenes / Ebionites came) are described briefly in his own epistles but also in Acts. Reading Acts 21 one sees that the Jerusalem Church that Jesus set up told Paul to dispel rumors he was teaching Jews not to follow the Law, and he acquiesced. In addition they sent a letter to all Gentile believers (Acts 15) apparently telling them to follow the Noahide laws (http://en.wikipedia.org/wiki/Seven_Laws_of_Noah).
I am not sure how the standard arguments for Christianity address this possibility. After all, proving that the resurrection occurred does not at all prove that Paul's claims about personal revelation and authority accurate. Mohammad makes similar claims of personal revelation. One might say that Paul is the real deal because Acts says so, but Acts was written by Luke, his student. Luke accurately describing the names of places etc. doesn't mean that his claims about Paul's miracles are actually true. In short if you look at it as a graph, it seems that Paul and Luke are completely disconnected from Jesus and his followers in authority. Except in one place, 2 Peter 3:16, where in a passage that sounds a little suspicious, Paul is endorsed and his opponents are attacked. I thought that would be strong evidence, but looking at http://en.wikipedia.org/wiki/Second_Epistle_of_Peter, it seems that there was always difficulty accepting this epistle and today the "vast majority of scholars consider it pseudoepigraphical."
So that kind of removes the last argument I know for the authority of Paul. Meaning, maybe Paul was the real deal and maybe not, but I don't know how to argue against the position in the link. It seems that Paul might be like Mohammad or Joseph Smith, and I don't understand the reasons for taking his writings or Luke's writings on faith, especially since his conception of Christianity contains many concepts Jesus did not teach.