I've modified the way the PGM priority works for Mame 0.130u1 to hopefully fix the bugs shown here in MAME (there is a bit of a speed hit as a result right now, but I haven't tired optimizing it) I'd appreciate it if people could run through the (working) games after the next release.
As for XingXings kov2p hacks, sorry, they're not acceptable in MAME. The real ARM rom should be dumped instead, hacking another one isn't a valid solution from our point of view.