long story short: more than 3 years ago Cave CV1000 was reversed and emulated by Demul-team, some time later with our help, information and support it was emulated in MAME too, some more time later Cave guys "asked" as to remove emulation of their's system (because they planned to re-release games for Android/iOS), so MAME and Demul removed CV1000 emulation (actually just disabled in public builds).
now it looks like enough time passed and Cave gain enough money from mobile ports, so CV1000 emulation was reenabled in MAME, as well as in next Demul release.