I need to think about this, but I don't believe McDie can handle dice having another attribute besides different #'s of sides and faces (e.g. color in your case).
It's possible this might be handled by the new card/cube/tile system I'm working on adding, which let's you add arbitrary 'attributes' (like color) to elements.
Since each die size can be any color, how did you want the model to set that up? Are there certain configurations? Is it random? Are there always one of of each type on a pool?