Tethering must have come after I uploaded my custom Carrier Settings file. Awesome!
Haha even the Apple employees are jealous on seeing me with tethering enabled. :-D
I have no idea how I did it. Sorry! I was hacking around with APNs in the Carrier.bundle itcc file
Tethering is enabled using a simple on and off switch. The screenshots below show that you can connect with USB or Bluetooth but Steven has yet to get Bluetooth working.