My wife bought this
http://www.logitech.com/en-us/gaming/wheels/devices/4172
for me along with GT5 last Christmas, she became a PS3 widow for a few months. I've had no complaints, it doesnt have a clutch pedal, that's really the only thing that I see is missing. You have all the same functionality, just slightly different layout - no paddles, use the buttons on the back instead. I don't know how much more I'd get out of the higher end models, including the Ferrari, although it is friggin cool.
One of the other members here - Equality7251 built one from an old racing seat and a weight bench. I'm still looking for both to build my own.