i've seen some data center miners running just barebone board on youtube.
https://www.youtube.com/watch?v=okI9rQNNtTQ
they don't even bother to put the miner inside a case with a fan. Just a barebone green board hookup to bunch of wires and a large fan.
That's technology from about 18 months ago. The power consumption for each board was much lower, and hence needed a lot less cooling as a result. I don't expect that Bitmain will be selling boards and not whole miners. Even if they did, it wouldn't actually save you any money. You will need their controller either way, and there's precious little to be gained by trying to engineer a better cooling solution. The "Green boards from 2014" weren't a complete miner, and hence needed the customer (i.e. the mine) to figure out the cooling.