Tutorial written by : [Plagued]

This Mod requires a little more work than just replacing one of the front ports, but it doesn't sacrifice any joypad ports.
You'll need - Blanking plate USB adapter (shown lower), soldering iron, wire, a dremmel or similar and an optional small pin strip.

Firstly you'll need to flatten the fan header, as it sticks up to far. Disconnect the fan, and pull off the plastic guide over the pins. Bend the pins over to the side as shown below. You'll need to fan the pins out a little as without the plastic guide the fan header would just fall off the pins. Bend them apart a little so you have to squeeze them together to plug the fan in, this should hold it firmly in place. If in doubt a little hot glue would work fine. The fan should now plug in from the side as shown in the pic to the left.

Take the two usb headers off the blanking plate. Trim the blanking plate down and use it as a template to mark out the positions of the new usb plugs and the screw holes. This is going to stay on the back so make sure it's trimmed neatly to size ;)
Take the motherboard and PSU out of the case.
Now drill/cut through the plastic and the metal shielding. Holding a piece of scrap wood against the metal to get a nice clean cut.
Check the holes by holding the new usb plug against the back and plugging something into it.

Decide which ports you want to use on the rear 1&2 or 3&4 (remember this won't disable the front ports you just can't plug 2 things in at once) I've used ports 1&2 as this xbox is mainly used for divx and linux so the dongle occupies port 4 on the front and the KB&mouse are now ports 1&2 at the back.
While the USB daughter board is plugged in write out the locations of the wires from each controller (ignoring the yellow wires).

Unplug the controller board and solder some short wires onto the 8 points (4 per usb port) on the rear of the joypad port connector.
You could cut the ends of the new usb ports and solder them directly, but I've chosen to solder a small pin strip (as you would find on a PC motherboard) to allow the ports to be unplugged easily. You can see the pins plugged into the usb lead above and soldered in place to the right. Simply match up the coloured wires from the front ports and the new usb ports. Making sure you have split them into their 2 separate sets of 4 wires.

Now hold your new usb ports in place and using the trimmed blanking plate screw them firmly into position.
Plug the new usb leads into your new plug on the daughter board (unless you soldered the wires directly), and there you have it 2 new usb ports on the rear, and your xbox doesn't look butchered.

Tutorial written by : [Plagued]