Joel also links to my response to Carrier, and emphasizes in the process that, while matters such as whether Jesus was the Messiah are questions that depend on faith, the question of whether there was an ancient human being around whom the movement later known as Christianity formed is not a matter of faith, but of historical evidence and deduction.
Mike Bird quotes Chris Keith in relation to the historical Jesus, unicorns, and Atlantis. It sounds like it should help the mythicists, but in fact it illustrates just how far behind the times mythicists are with respect to the discussion of history, memory, and scholarly methodologies.
The blog Irreducible Complexity expresses well what mythicists would need in order to be taken seriously – someone who does what plenty of mainstream scholars have done, namely challenge the consensus from the inside offering persuasive scholarly arguments. While Mark Goodacre has not persuaded everyone to abandon the Q hypothesis, he is a respected member of the academy because his work is serious and scholarly, even if not found decisive by many of his peers. Challenges to scholarly consensus are constant in the academy. The problem with mythicism is not that the academy doesn’t allow challenges on this point. The problem is that mythicists are not pursuing scholarly careers, scholarly publication of their arguments, or anything that does more than try to don a thin veneer of the appearance of scholarship while lacking the substance. If mythicists want to be taken seriously, they need to get over their persecution complex and actually do scholarship.