Examine the trackballs carefully before purchase, as they are not cheap to rebuild and Bob roberts is out of the parts. Arcadeshop still seems to have them, but you can be in $140 in rollers, bearings and balls if all of that needs to be replaced (and they always seem to need rollers and bearings).
All of that said, if you indeed get one, the control panel is nice, and decide to part it out I will shamelessly take the control panel off of your hands.
Been trying to lock down a nice control panel for mine for a while.