Im wondering about the card width.  Looks larger than 2x slots and thats the general spacing on most motherboard every second slot for PCIe and very few cases support more than 8 card slots.

Also your right they were using 4U cases in their examples so that still matches.

They really need to give specs like how long, deep and wide the cards are plus details on the radiator and tube length.  Trying to work out where to mount everything is kinda important for people trying to decide if they can use these things or a refund is the only option.