I think they do. And if they can buy it, we can do it also.
How hard is to made miner like that when you get chips, using directly raspberry pi on it.
you still need the firmware to communicate with the chips.
The electronic part can be done, but might not worth it if you only plan to do a few.
http://www.innosilicon.com/A2.htm
200$ each chip if you order 50 pieces
roughly 10000$ = the actual price for the complete miner with 48 chips
these chips are too expencive and I am soure you can get cheapper one.
And if more people takes it we get discount also.
We need to search cheapper chips
Gridseed GC3355 chips would cost nothing to buy now. Could worth the try, plus the firmware and the design to be improved already exists.
It all depends if they sell the chips and if they sell for really cheap.
They aren't that power hungry to move 28nm now. simply marketing.