Alright here is a WIP. What I did here was painting myself a basic colour palette to start from, with a layer under my line work. The colour palette is not final tho , will be more worked out during the painting process. When basic coloring is done I then lower the opacity on my line work so it blends in with the colored layer. Added a scratched metal plate texture set to softlight to get a little bit of texture and to break colors slightly. Then I merge all layers. ...and keep a copy of the linework separate.
Then its all about painting define shapes, check references for material study, back to painting and thinking.
I did some quick rendering on front of the machine to show a bit how it could look like. I did much of the design job with the line drawing so I guess many of you will know how the process will go on. painting painting rendering rendering.
I will keep you updated!