Appearently the G25/27 pedals can also be attached to a DFGT if you open it up and reonnect the wires: https://www.youtube.com/watch?v=eAhNhWNNm-8
Does not work for the clutch because the DFGT electronics have no use for it. But the clutch-pedal could be connected by combining it with any other old USB device, like an old gamepad or joystick.
Well, all a bit cobbled together. Happy soldering