What support is there for the Jehovah’s Witness translation of John 1:1?

Rather than the more traditional “In the beginning was the Word, and the Word was with God, and the Word was God,” Jehovah’s Witnesses use the New World Translation, which gives John 1:1 as “In the beginning was the Word, and the Word was with God, and the Word was a god.” In asking what support there is for the Jehovah’s Witness position, this question is not about whether the New World Translation is correct and is not seeking a hermeneutical response, which is already provided here . I am looking for biblical or historical texts that could support the Jehovah’s Witness translation.