The balls ARE available, when i bought mine it came with a  full set of replacement balls. They are not as good quality as the originals though.
 I was told that they came from PBR.. might be worth checking with them via email... after all.. someone made mine!

Let me know if you need anything else for this machine.. i need to get new armatures made for the balls in the BG, the original plastic ones are cracked etc. These will be CNC routed from sheet aluminium and the cost for an extra set is minimal as im paying for materials and time on the router.

,.. i also have spare plastics... but no BG im afraid.

Is this the bank A ball thats been on Ebay a lot?