You can color multiple selected channels via the color palette icon. This can even be done in Cubase 6.
Now, if you mean coloring the entire channel strip, then I agree we could benefit from that. Although, I honestly don’t find it to be essential for my needs given the fact that Steinberg has now added track icons. One could make icons with different colors to achieve a similar effect. GIRO, you did a good job with your custom icons. I like what you did there. If you simply color them differently based on the type of track (i.e. drums = red font, vocals = green font, etc), I’m sure you would be able to navigate through the mixer without issues. Just an idea 