Ah. Well, the scripting in oblivion is just that - scripting. It doesn't run on the hardware as such, the scripting engine (which differs per platform) runs the script. It simplifies cross platform development enormously, as you can use the same resources for each platform, however the core of the game itself does require changes.
Okay. All that said, I would still imagine that it'd be a far easier job to port between PC/360/PS3 than it would be to have to actively make large changes to the interface/controls such as e.g. having the menu screens 'streamed' to a new screen on a controller and made touch compatible, which would be a large structural change to the game itself.
So i think the possibility of a port depends on how large a push there is on whatever Nintendo's new innovation turns out to be; or if Beth are actually sold on it (e.g. using touch screen to do the 3D object investigation would be pretty damn cool)