DV Info Net - Is frame-readout-speed a property of the sensor or processor?

Here's a good geeky question for you!

Is the frame readout speed a property of the sensor or of the processor? By "frame readout speed" I mean the speed at which the camera scrolls through each line of the sensor to capture a single frame. i.e. a slow frame readout speed produces the infamous "jello-vision" or rolling shutter artefacts.

Why do I ask?

A new Nikon rumour was posted today. The rumoured specs for the D300s (the rumoured replacement for the D300) include

Quote:

"The new processor speeds up AF and significantly increases the quality Movie mode as compared to the D90 and D5000,
Movie - mode: 1920 * 1080 at 24 fps Quicktime MOV, H.264 codec"

Let's assume for a moment that this rumour is true (there's every possibility that it is a fake). If the D300s had a sensor from the D300 but with a faster processor then would the D300s have a faster frame readout speed than the D300? As I understand it, the frame readout speed is a function of the sensor itself, not a function of the processor. I suspect that a faster processor would allow the camera to demosaic and downsample more elegantly than previous Nikon cameras (which did nasty things like row-skipping etc) but that the frame readout speed will remain slow.

My hunch is that the D300s will have nasty rolling shutter. Are there any reasons to believe otherwise?!?