The PSU choice was relatively simple. Requirements were Gold+ rated, fully modular and top quality. I used the eXtreme Power Supply Calculator Pro to figure out what kind of wattage I would need, and specifically looked at the 12V rail to give me the amperage I need. Well, it came up with this overview:

So it was clear I needed a 1200W PSU. I mean there is nothing bigger, even though this calculation is based on only 20 HDD's and not up to the 31 I have room for. This takes into consideration that the two BD-R burners would not be used at the same time as the full CPU/GPU power and from what I found available the choice came to the Corsair Professional Gold AX1200 model.

The PSU has arrived and has been installed.

That gives me the first practical problem in this build. I need to place the quad fan mount at such a position that the fan of the Corsair PSU, which is larger than the fan openings in the mount (13.5 cm versus 12 cm) can exhaust the maximum amount of air. But that may make it dififcult to place the two planned exhaust fans in the upper two spots. The top left one is no problem, but the right one may be a bit tight. Well, I'm still waiting for the Noctua fans, so maybe it will just fit in, otherwise I have to move the fan mount up by 12mm. We'll see.

Of course it is great to have the PSU and the heat it causes far removed from the CPU and motherboard in the other side of the case.