TNT Amusements has had one in his bargain basement videos for a long time. Needs a monitor and a gun, but he has the cab and PCB and he'll ship anywhere. Here's a (time indexed) link to his overview of it in last bargain basement video
I have two Beast Busters 2...its the second version that runs on the Neo Geo 64 system...but no monitors in either...but they are cheap...you can hear them working...