Head over to Jim Darlack’s blog and download Dean Deppe’s “The Sayings of Jesus in the Paraenesis of James.” Jim quotes Richard Bauckham as saying:
Deppe’s very thorough study (unfortunately not easily accessible and so not used by most scholars writing subsequently) probably takes this method of approach to the relationship between James and the Gospels as far as it can be taken (see pg. 117 in “James and Jesus” [pgs. 100-137 in The Brother of Jesus: James the Just and His Mission; eds. B. Chilton & J. Neusner; Louisville, KY: W/JKP, 2001]).
If Bauckham approves then it has to be at least worth checking out, right? In any event, Jim has uploaded the updated version which comes in at about 500 pages. It’s a large file (about 30 MB) but I’m sure it’s worth it.