Here's what I found out about this bass:
Custom bass - CMB4 - 90C5988
top: Ebony
accent laminate: Maple
body: Mahogany, Small Standard shape
neck: 5-piece Maple and Purpleheart, short scale
fingerboard: Ebony with pearloid oval inlays
pickups: AXY
controls: Signature
finish: polyester satin (unusual!)
originally made for: Rokkomann, Kobe, Japan
birthday: May 25, 1990
There's no other contact from this bass.