haha I SAW IT @ lethalrabbit : everything is chroma key(greenkey I guess) the little man is just keyed on the guitar, I hope for his sake he made key points (white black dots) on the guitar otherwise its a hell of a job. every frame has to move along the guitar to put the little mgm in. Otherwise it doesn't look that naturall
Really easy tbh: [youtube]http://www.youtube.com/watch?v=zwMs8di7HVM[/youtube] You can do so much with a greenscreen (and some motion tracking)