Create a multi layer vector drawing

I have a professional laser marking machine at my company that is very good at annealing metals to make color. See these links for examples: [login to view URL] I am attempting to make some interesting laser marked art pieces, but in order to do so I will need to downsample each art piece into color separated layers and turn each layer into a vector outline. It is very important that the vector that is created has only a single line output as opposed to a double line. I attempted using programs like Inkscape to turn trace a bitmap into a vector outline, but it would only output the outlines with double lines. My true goal with this project is to develop a method for creating these layered vector drawings so I can repeat the process with other artwork. The first piece I want to recreate is the hokusai great wave painting: [login to view URL] It is a good piece to start with because it has a limited number of distinct colors, making for few needed layers. I'm hoping somebody out there already has the answer to my problem, so it would be pretty simple to let me know how it is done and produce the vector drawing for me. If everything works and if you are interested, I could also help you make your own cool laser artwork of anything you would like as part of the payment.