History and Biblical studies - a short rant

What has fascinated me is how little it is argued we can know about the authors of the gospels. Many scholars are content to argue that the gospels were formally anonymous and as Sanders suggests, the titles began to "suddenly appear about the year 180". On the other side of the debate there are a number of Evangelical scholars (Craig L. Blomberg is an example, or pickup an Evangelical commentary) that argue on the basis of various traditions that traditional authorship is historically plausible. Similarly, Martin Hengel in his The Four Gospels and the One Gospel of Jesus Christ makes a sound case in this regard. However, I am sure I have been conditioned to regard such views with scepticism as they would, God forbid, confirm orthodoxy. I know this view would lose favour with many scholars by its very nature, as one can never be too sceptical of the orthodox tradition.

However, my question is where this scepticism goes when approaching the extracanonical literature. The way Crossan talks of how Thomas was originally collected under the authority of James the brother of Jesus, and then in Edessa a second layer was added under the authority of Thomas does bedazzle me. Maybe I am simple minded but the evidence brought together for a conservative approach to gospel authorship seems so much more historically sound than the cryptic readings of sayings 12 and 13 of Thomas or the secret source behind the Gospel of Peter and how they produce a primary layer that can circumvent the canonical sources (well, except Q which we can easily circumvent by applying our circular criteria that proves that the early layer we expected to find was in fact the early layer!)

Although probably not the best example provided above, it appears that at many times 'conservatives' seem to care more about the historical evidence than their 'liberal' counterparts. I do not expect anyone to agree with me, but my approach to early Christianity and Jesus studies from within the context of an ancient history department (and law school but we don't talk about that) has me seeing evangelical NT scholarship as something that shouldn't be pushed to the periphery for ideological presumptions but seriously considered. Then again, it may just be that I have read some of the better scholars from the conservative side and am just so frustrated at hypothetical redactions of everything to support Jesus as cynic sage. Or it is that the more I read Davies, Koester, Crossan, Mack, Robinson, et al the more delusional I get about where scholarship stands and I artificially believe that conservative, and even mainstream, scholarship is ignored.