I have 2 builds with that cabinet. At least, I think it's the same cabinet. I sold one and kept one. Here are a couple pics.
My advice, keep the trackball since all the engineering is done. I did both and spent a lot more time building a new CP than just adding in a trackball.
In the Golden Tee cabinet I kept for my collection, I added 2 more speakers and used some halo rings facing inward to give it a cool glow. The cabinet itself is rock solid, but mounting a monitor is a little tricky. The solution I used involved buying an oversized piece of tinted plexi, then mounting that directly to the cabinet and then butting the monitor straight up to it.
Good luck.