Has any one thought of combining a couple of s3's together sort of like the C1 but not changing over the heat sink. I mean Sort of like how the s5 is done. Would it be worth it? I mean have one controller controlling all 3 s3 instead of three separate units?
Yep, I have done some testing with these. Original S3-controller was propably meant to control more than two boards. It's schematics show connections for 4 hashboards. But problem is that firmware has support only for 2 hashboards. In hw-level I can read code from pic-mcu and reprogram it, but changing that code would need assembler coding. It's propably easier to write new code to do that. But coding isn't one of my best skills. Open-wrt module's software is also capable to update that pic's code so it might be possible to tweak it's drivers. But again,it's beyond my knowledge.
There might also be a reason why they dropped that pic/ar9331 controller out: it has only 2 physical uart's. Some of pins can be programmed for uarts but I'm not sure if that pic is fast enough for it. Some wiser men have told me that it works if the baudrate is low enough. But I really don't know, I'm just a hobbyist.
Ofcourse it can be done with usb/uart adapters like cp2102. You only need to do level shifting too and provide 1v8 and 3v3 to hashboards. It works, I have tested it, but every hashboard needs its own cp2102 adapter. I might try to build an adapter with cp2108 in it. So it could drive 4 boards with one usb connection. And it should have some pwm-controller for fans too.