If you are willing to wait, microsoft has a force feedback wheel for xbox 360 coming out in the very near future
That won't work on an Xbox though, and probably won't add anything to the backward compatible games that are working on the 360.
Like I said, in my other post...
The Fanatec wheel does have motor driven feedback. It techincally kicks the wheel just like the driving force pro does. It just doesn't do it with specific force data.
When you are using the Driving Force Pro with Gran Turismo 4, you can actually feel the aspects of the road, and the forces of the car, the varying resistance on the wheel in turns at different speeds.
You don't have that kind of realistic feedback with the Fanatec wheel, but it does do a pretty good job at faking it (after all the controller rumble that it is basing its forces off of are also related to your gameplay, just not to as detailed an extent as what you get with PS2 or PC force feedback).
I too love the racers on the Xbox (Forza, PGR3, OutRun 2, RalliSport Challenge 2), and the Fanatec wheel does add greatly to the experience of all of them.