You cant off the shelf. Im the one that designed this system with Padrino. My personal prototype systems are running 10 GPUs of a Gigabyte board. It requires very low level changes to how the board BIOS operates.
How have you started 10 GPUs? My personal record is 8 at the moment. And I want to start 12. What OS?
You can run 32 cards from one Motherboard using Linux Zcash miner under Ubuntu and a combination or risers and PCIE-X3 splitters. Not sure why you would want to, but you can.
Even with pcie switches how are you compiling the kernel for 8+ gpus? Much less bypassing current mobo restrictions to get over 16 gpus?