I got lucky and picked up one last year after playing one at the NW Pinball and Arcade Show a long time ago. Estimates place the numbers produced at 200 on the low side to 500 on the high side, but I've never come across a definite number, just like there is no real manual. It apparently never made it into full production and therefore never received the support from DE that larger releases did.

It's a very cool and unusual game. I have it on location and, if you judge by quarter drops, it's as popular as Ice Cold Beer!