I am sure this has been done before, but looking at the heap of wires and crap on my desk I found enough parts to build this...
You'll need an old Nintendo Controller or some other clever case
$0.10 USB hub from China
Solder and Iron
Screwdriver, side cutters and pliers, file helps too.
So lets dive in!
Step 1: Gut Controller
You wont need any of it, except the buttons. 6 phillips screws hold it together. Do save those buttons! Just glue them in place before we get too far along.
Now thats done, pull one of the sockets out of the USB hub to measure, mark out where to cut the plastic and go after it! I used side cutters to split it down then pliers to snap out the bit, filing it smooth..
Once you got the hole made, glue it in place! I used hot glue, sticky stuff that doesnt snap free when set.