i ever was looking through the mob textures of SphaxPureBDcraft, and actually found a Herobrine texture, probably from a different Herobrine mod than mentioned by sed11
something i have forgetten to say: the update logs of minecraft in the minecraft update logs, since Beta 1.7, there was always a point about Herobrine mostly: -removed Herobrine what was noticeable about that, was that this had effect on the Human mob, or as known in Single Player Commands, Monster (49). in the official release, Minecraft 1.0.0, there stood in the update log again removed Herobrine, which was actually removed human mob. thats the truth behind it