Sorry to resurrect an old thread. I'm not even certain that anyone on this board would be interested since the DigiKing arcade machines aren't even listed in the JZ47xx devices list.
After years of sleuthing I was able to determine that DigiKing isn't even the name of the manufacturer. DigiKing is a brand used by Guangzhou based manufacturer Toycenter
for all their electronic games, so the proprietary Neo Geo software these devices use could have been internally developed by them.
Examining the board inside I was able to determine the ZL-118 and ZL-128 both run the JZ4755. Neither machine has a micro SD card glued to the board so the likelihood of installing custom firmware is low. As I suspected, Machines that run the same linux-based OS also use the exact same format of MVS roms. These files are significantly larger than the dingoo brand mvs roms or even the Neo Geo X's FBA based mvs files.
The "SuperGames CD" in question was included with the original model of the PAP KIII, PAP Gameta II as well as the PAP-1000. After years of searching I have finally been able to obtain a copy of this disc. These games run just as well as the ones included in the arcade machine's internal memory.
If anyone who has any of these devices limited to this particular romset is looking to add more Neo Geo games, please send me a message and I'd be happy to help out.