Here's a quick question. Will GT5 be compatible with Logitech G25 Steering Wheel or will there be a new Steering Wheel designed to be compatible with GT5?

GT5 should work fine with the DFPro. Fantastic wheel. Mine saw plenty of use until I got a G25 which is also just awesome. Now im upgrading yet again to Fanatecs 911 turbo S Clubsport edition wheel as I need something that is compatible with the X360 and options seem quite limited thanks to Microsofts closed peripheral support. I wonder if GT5 will support the pedal feedback that is in the clubsport pedals? Im also curious to see if we get a GT badged G25 from Logitech.
I dont understand why you fear some kind of uncompatibility with all the wheels we know. If we're lucky GT5 will even have the G27 support.
I just hope that GT5 will take the DFP because I don't want to spend money on a new wheel.
It should being that it's only a bit different from the G25 (from what it looks like).