I beg to differ: when you switch on a Viper, it does something very, very similar to the out-of-sync-shutter effect, while its mechanical shutter gets up to speed and synchronises with the electronics. With a frame-transfer CCD, the image is transferred line by line across the face of the sensor (into, effectively, another dummy sensor that's kept under an opaque shield). The image is very literally "pulled down" (or possibly up), moving across the sensor. If the sensor is still exposed to light while this is occurring, there's nothing to stop the photosites contributing extra charge to the charges being transferred through them.
So yes, if you put the shutter out of phase on a Viper and possibly on other camera systems using similar technology, it will do similar things. I'm not aware it's actually possible to do that, mind you, so this is really only of academic interest.
The effect is really quite easy to simulate in postproduction, anyway: take the image, crush everything you don't want in the effect to black, apply vertical blur, move upward to taste, composite back over the original with "add" transparency.