Usually, I'm not much of a purist, but when it comes to Japanese (candy cab) designs I am, so you might not agree with me. I think a trackball should be used in old school Mame cabs, not in Candy or Vewlix cabs. It looks absolutely horrible to me. Then again, it's your cab, so if it fits your taste, go for it.
Regardingthe CP design, I'm not really sure if mixing the old school Champion edition style and the newer, more modern SF4 style works... somehow, they clash too much for me. Sorry for being so negative, but like I said it's your machine, so in the end, you should it exactly the way you like it.