I have used that effect(cloning a footage and using like in the music video).what I did is,first applying keylight to the green screen footage,using different rectangles as alpha matte(just like ECAbrams split and slide tutorial)and finally applying Trapcode echospace plugin from RedGiant(it is like echo,Ae plugin but with more controls).you can then adjust the repeat,opacity and x,y,z offset….
I hope it helps you!