So far so good:

Now, let's add some additional controls, first a 2.5" trackball. In retrospect, I don't know if I would have used this circular cutter. It took a long time to cut out. I didn't bother to remove the overlay when I cut this because it had some cigarette burns and damage to it. I have brand new replacement original Neo-Geo parts that will be stored inside the cabinet and will put a new overlay on later.


Cut a hole for an Oscar Vortex too, and mount both:


Hook up the i-PAC and realize that I was a total dumbshit:


Ok, with a little grinding, that's fixed... I know I can't be the first person who mounted a trackball off-axis.
My girlfriend was like, "Well this works perfectly if you stand off to the side!"
So there it is:

I'm hoping to add some extra small buttons to handle stuff like mouse-click and other functions. Although there's probably a way to program one of the PACs to do key combos. I'm waiting a control panel overlay and then I just have to sort out the nightmare of FE and Mame configuration, which still plagues me here and there, but it is workable and playable....