Updated 2014 Dec - I've just added these pictures of this guy running in Unity 3d, along with his updated/consolidated texture sheets. I'm using three materials all together: a totally transparent specular/glassy material for his outer eyes, a transparent diffuse material for his eyebrows and eyelashes, and one normal-mapped specular material for everything else (head, body, eyeballs, teeth, etc). If you'd like to see this character in action, be sure to check out my Ragdoll project.
Original Post 2014 Oct - The head mesh here has 4045 verts (or 6763 verts including the eyeballs, teeth, gums, eyelashes and eyebrows). For the diffuse and specular maps, I used a zBrush FiberMesh to quickly make the eyebrow and stubble textures, the skin is occlusion, noise, and Photoshop painting, the eyeball texture was created from some layered photographs that I took myself, and the eyelashes are just painted in Photoshop (I used eight planes, two for each set of eyelashes, to keep them from looking too flat).
This is actually the second subdivision level, so if I needed a lower poly count everything could be re-projected without any additional work.