You can apply any type of material to each mesh on your high mesh or individual groups of polys, give it a color, then bake a diffuse map in transfer maps. If you use RGB or RGBCMY its relatively easy to create a script to separate all of the layers in photoshop automatically. Unless you're just talking after the mesh has…
you can do this with the regular batch bake function as well. Here is how. I use a MIB_illum_lambert for each group or color etc. I set all of its attributes to the targetcolor (ambeince, ambient, and diffuse) I make sure that there is no lights in my scene, and that "enable default lighting" is turned off in my render…