Sorry for being MIA - too busy with other work stuff now.
Hope I can escape for a day or two to continue testing the rigs.
The one Phil got requires an ATX PSU to power 3 molex and 3 sata.
You can use a server PSU to compliment higher end cards - probably similar to the 6 x slot ONDA D1800 BTC board.
Phil - did you received the 2nd D1800 board?
I have tested that board with P106s, and work in progress R9-Nanos, R9-390, RX470 and RX480s.
The current board that I am testing has onboard CPU/RAM with all PCI 6-pin power, and 9 x PCI slots, see the following:
7 x 6pins power in, and it has 9 x 8pins on the side that goes to the GPUs (the cable that I got was 6pins both sides for lower end GPUs, but supplier say, i can use 8pins too for high end cards).