The usb controller I'll be using as a base has finally arrived from china.
And I got usb audio to work, so that's good!
Here's all the gang together in a cardboard box for a quick test. I think I'll need a few more USB ports, but this is fine for now. I can probably drop ethernet as we have wifi, but with one for the controller, one for wifi, and one for audio, I'm left with just a single port. I'll probably try and pick up a 7 port hub... though I think they're just two four port hubs so I might stick with those.
If anyone has done anything with speakers and a headphone port that can also be used, please point me to it, as this is something I'd like to include in the design!