I have seen a white pixel on my canon 7D on the LCD screen while shooting video. This is not a dead pixel on the LCD screen though because when i use the digital zoom buttoms the relative size of the dead pixel changes also. So it must be a dead pixel on the sensor.
However, when i upload the footage onto my computer the dead pixel seems to have vanished (thankfully).
I know this is lucky, as my footage doesn't contain the dropped pixel, but i just wondered if anybody had experienced this before? or how to remedy it.