I guess I have to follow you around everywhere you post this and post my response:
You can't prove a negative so there is NOT overwhelming evidence that Jesus never existed.
All of the direct evidence that exists has been collected for you in one library called the Bible. After contemporaries have done all that work for you it is disingenuous to say that there is nothing else except what was collected and preserved.
The burden of proof does not lie with those making extraordinary claims. They are there for you to accept or reject as you will. Jesus made it clear that He had no intention (deliberately) to give you unassailable proof. He provided enough evidence for those who want to find Him and not enough evidence for those who don't. It's a filter and filters are designed to let some things get through and keep others out.
I laugh (sadly) at those who sit on the outside demanding that Jesus do even more than die for them. They want to be spoon fed while keeping their mouths firmly shut - just like a 2 year old rejecting a big spoonful of coconut cream pie!
RE: Is there a scientific basis for Jesus Christ?