Thanks for all the replies, but I found a copy!
I just made an iso-image from it and tested it in ePSXe: PERFECT!
Multiplayer Mr.Driller! YES!!!

I have a Mr. Driller G jamma pcb (best and latest of the series), and love it so much I bought another just to get all the arcade artwork that came with it.
Is the JAMMA version you have in English, or is it also only released in Japanese?