I have been experimenting with this form. Here is one that I powdercoated black and the back end is elk antler and ebony. I won't mention the price for fear of being thought an idiot.
Maybe it is just the photo?? But if you hadn't told me it was a cartridge pen, Bill, I would have never guessed. Interesting experiment; but if you are trying to emphasize the cartridge aspect of the pen, the dark powder coating may be counter productive.