I have built brains 1 and 2 board s9's I sold some in marketplace they are very good.
I recently got 3 custom s9 sized board by another builder they are great and would be exactly what you what
but the builder has yet to contact me about buying 10,50,100,500 boards.
You are best off either buying a pre built custom braiins s9
I am not selling them but these were the threads.
https://bitcointalk.org/index.php?topic=5243761.0https://bitcointalk.org/index.php?topic=5160194.0basically like these.
this is the better board but they have not given me a price for more
https://bitcointalk.org/index.php?topic=5253561.0the better boards do 52-59 watts a th
the braiins are about 82 watts
the brains can be 2 boards and will down clock really low
the better boards can be 1 board and are more limited with down clock say freq 400 to freq 550. and 285 to 410 watts.
I don't think I will get the better boards any more.
If you can find a cheap watts miner m10 and set to low it is good.
I have a whatsminer m10 doing 14th and 900 watts about 63 th
https://bitcointalk.org/index.php?topic=5257186.0it is in these threads above and below
https://bitcointalk.org/index.php?topic=5221489.0