The ONDA B250BTC-D8P 12 GPU MINING MOTHERBOARD is available in the USA from this site:

https://www.cryptomined.com/index.php?main_page=product_info&products_id=356

He also carries cases for that board.

https://cryptomined.com/index.php?main_page=product_info&cPath=245_358_364&products_id=363&zenid=f06um7neuoi763if0bj5jt5tb5

That is probably the best rackmount design i've seen yet to allow the use of these 1x pcie slots and fitting 12GPU's in a 4U case.

It does look nice, finally one with room for 2 PSUs. For now I've given up using cases and I just hang my GPUs from wire racks though.