I'm so sorry there were no new clues and that you didn't find your sweet boy. My heart breaks right along beside yours.
. I'll keep praying for a happy ending.
Did you visit the Orange County Animal Service that I read about in a previous post? That little fella looked a lot like Benji. Perhaps the person you talked to on the phone was mistaken about him not being neutered. I'm just grasping at straws and want you to find him so badly.