Amazon has their own custom built 7 port usb 2.0 hubs with 5v/4a adapter for $19 shipped (prime). Ordered 7 for an antminer project, i'll report back how they work out.
Actually they were $12 at some point ... I should've ordered more of them at that time. I've been using them for testing various quantities of NanoFury boards and so far they've been performing pretty well.