Biostar TB250-BTC PRO - 12 pcie slots
ASrock H110 Pro BTC+ - 13 pcie slots
and now the ASUS B250 Expert Mining 19 pcie slots
I will say it can be a pain in the ass to track down issues with that many GPUs.
How do you get 12 GPUs in a rig? What board has 12 slots?
What are the odds of me not 15 mins after posting this question frying all of my mainboard pcie slots an a rig by touching the pinout on a card to the case? How did I manage to fry them all in one shot? lol