i think that you can have a better power efficiency with raspberry pi 3 cluster instead of those mining stick, since Raspberry pi has just 5~6 watts per modest (AFAIK), where there are at least 24GFLOPS per node, should do around ~10 GH/s per node. hope i didn't make it wrong.
Hmm, that's an interesting idea, too. How did you set it up? I just tried to find an easy step-by-step procedure for setting that up to no avail, so any help would be appreciated!