I'm a fan of "different" colored micartas as well, and some of those blue or red G-10 scales I've seen recently are also a welcome relief to my eyes than nothing but basic black, black, black.
I have red/black laminate micarta scales on my Rinaldi TKK and love the look, the definition and layering gives it a very nice grain, like the sample shown by Lynn.
I also have one of the new Desert Warfare Mean Streets with the tan micarta, and think it's a great color choice as well. I don't think some of these alternative colors will show dirt and grime any worse than the basic black will, and the colors should actually give a "patina" of use and character that, IMHO, make a knife more attractive over time.
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Don LeHue
Rome did not create a great empire by having meetings...they did it by killing all those who opposed them.