The final result:
Its amazing how easy it is to create 2d assets opposing to the 3d stuff. The steps from the "concept" to the thing you see on screen in 2d are really trivial compared to the 3d. Here's how i do it.
1. Do a nice sketch with a pen on paper
2. Cleanup the sketch a bit by copy it on the window :)
3. Shoot it with a webcam/camera
4. Trace it by hand in inkscape
5. Cleanup the traced splines and actually generate the final vector graphic.
6. Export to raster
7. Do diffuse
8. Do cel shading
9. Do Decals like text marks etc.
Here are some funny "concepts" :):
Entirely done with a pen, paper and a mouse. Kudos to the people behind the amazing Inkscape program.