It turns out that you can induce pluripotency with all four Yamanaka factors, but there's a significant risk of the pluripotent cells turning into cancer.

But by using only three of the four factors, you can still induce pluripotency, but with much lower cancer risk.

I think that cloning individual organs is much more promising than cloning entire bodies and then harvesting. Much less work, you don't have an entire body you need to either upkeep or dispose of.