Do some research then, because one exists already. Google Fanatec.
I'm a big wheel fan, and I really like what I've read about the Fanatec + Forza 3 combo. However, from what I've read, even the multi-system Fanatec wheels are really only good on the Xbox 360, and even more specifically, with Forza. Several reviews mentioned that they don't feel right with Playstation 3 games, for example Need for Speed: Shift and GT5P.
The new Fanatec PC-dedicated wheel (Porsche 911 GT3 RS Wheel) seems really sweet with the fully adjustable pedals (available separately for the 360 bundle, but the full metal pedal set is seriously expensive on its own) and the alcantara wrapped wheel. As much as I would love to buy a Fanatec wheel + Forza 3, I think I'm going to spring for the G27 + GT5 (when it's out.) I may end up buying Forza 3 anyways and see how well I can do with the controller - although I may snap and just end up ordering a Fanatec wheel if I *really* like Forza 3.