comments:
Yup, a Corsair RM1000x Shift. I has enough modular cables and enough amps (in the 5V rail in particular) to handle these 13 drives without a problem, and probably a few more. If I wanted to expand the setup much further I would add another ATX PSU with an adapter board like this.
That's the neat part, I didn't. I am using a Corsair RM1000x, which came with enough modular cables for this and has enough 12 and 5V rail amps to support the drives. Now, when I expand it to the final configuration of 6 modules, I will probably need to add molex connectors to some of the existing SATA power cables. If I go beyond that, then just to be sure I would add an extra PSU, with one of those dual PSU relay boards to power it on at the same time as the main one.