This is fanart bust of Boman from old school 'Rival Schools' game. It's using Dyntopo and Vertex Paint. Better seen with Blender 2.74 or newer because it uses new viewport Ambient Occlusion Feature.
Reference: http://www.creativeuncut.com/gallery-10/art/rs-boman-delgado.jpg
Timelapse: https://www.youtube.com/watch?v=DDj3yo3mjSw
Thank you for taking the time to share your technique and work. Found it useful :)