Hi, maybe I can contribute a little. We use two systems set up for 6 screens each. Sometimes I get that pixel line crossing over to the next screen, and sometimes I don't, it seems that is a problem with sync signals, our systems go through VGA matrix switchers and I usually correct the problem by resetting my matrix, we also used one of the systems once to feed 19" LCD computer monitors.
I had the lines crossing over, and could correct it because I wasn't using any switcher, I pushed the auto setup button on the monitor and voila, worked like a charm.