Silent Bomber Original Sound Track
I've been trying to catch this on sale for about a year now, checking all kind of japanese auctions - still nothing, no traces whatsoever.
OverBlood Original Soundtrack -GM-PROGRESS-10-
Seen it on Ebay several months ago for $1500, while the game itself sells for about $2-3.
Abe a GOGO Original Soundtrack
CD was available in Japan only, for a western game.
Nowhere to be found nowadays, I got very lucky and randomly bought it from a guy on Facebook for 150 euro, which was a pretty good price I though. The guy asked to sell it back to him a week later.