Couldn't help but necro to say that while the initial outlay would be pretty high, the donut courses and tubes are reused. Running costs would be low, especially with the number of spare koAlices lying around from using the bigger rapists to quick-produce desirable breeds of yukkuri. The biggest expense would be paying the guys who watch the donut courses and pull the fully-hardened ones.
Also, I want to try something like that. Mmm, custard pop...