is there a filter that can help cut a lil of the vertical smear casued by many camcorders? post your tips/opinions/ideas

No, it is a phenomenon of certain types of CCDs and there is no cure except changing cameras.

Is this not caused by too hot a light source?

Yes it is. Too hot for the aperature/speed/gain settings of the camcorder.

What happens is that the charge is bled off of the CCD pixel so much so that the charge dissapation spreads to the readout circuitry and even adjacent pixels, depending on the degree of discharge. Note that this is sort of an operative description and not a complete technical truth.

I shoot with the PDX10, rather known for it's strengths as well as it's weaknesses, one of the latter being vertical smear. In an effort to avoid provoking this smear, I try to avoid strong light sources, both in frame and even above frame, where the smear can still streak down into the picture, though the source isn't exactly visible.
Problem sources encountered thus far:

headlights
streetlights
candles
chandelier lights
stadium lights


Finding out ahead of time whether there are problem lights on uncontrollable locations is a good step towards avoiding smear. Non critical time spent with your camera out in the world will add to this specific type of safety instinct.
If you can't test for this beforehand, try to frame your shots in ways that avoid these sources,. My best and only advice.