I ran 37 USB devices from a raspberry pi for a while. CPU can get swamped if you're not careful going much beyond that. The newer antminers are much faster per device so you can probably get a lot more hashrate without clogging up the pipes.
30 AMUs
5 BPM Blue Furys
1 BFL Little Single
1 BFL Jalapeno
Total of 62 GH/s
]
Is this stable? I mean, I tried once, but it started to not recognize all the miner that I had plugged on the USB hub