I have in fact heard of both these men, and I agree with you that their reputations and stories are likely to have been borrowed in the construction of Pauls' cult.

But my thought was that there might have been two men - near or actual contemporaries - named Yeshua active in Judaea at the time. One being an Essene preacher and reformer from Galilee, the other a Davidian descendant and Zealot leader. This would explain a lot of anomalies in the gospel accounts.