Which would make them no more free than the ones mentioned in my post. In fact they'd be less free because you'd have to "pay" the resources to make whatever rocks end up on the private farm to mine them from.
Considering the fact that the way the director has stated in the past he wants to curb summon golem's power is mostly through limiting the supply of snow golems, I highly doubt the cuilin stones being added to private farms will provide finest stones, or possibly even fine stones. You're probably going to get big gray rocks you can mine low grade and common cuilin stones from, just like the ones in Sliab Cuilin. Considering how many rocks there are in the public quarry, and how I never see them being much competed for... and the fact that it is already ridiculously easy to get your own private, instanced quarry of them... I don't see how the option is going to be a helpful addition to private farms.
Unless they just plan to give us access to fine (and maybe finest) stones much more easily than the existing source. But that seems contrary to what else has been said.