Well, there are some people reporting it, true... But if you replace Panasonic with Sony or LG you get the same things being reported on those TVs instead. I guess it's more of a 'feature' that flat screens tend to fail with lines on them, rather than total failure or loss of one colour gun like you might get with a CRT set. How old is your set?
My set is 22 months old. As you say faults do seem to be a feature of flat screen TV's which is a puzzle to me. LCD monitors seem to last for years without problems which is why I question whether a plasma is a better buy than an LCD. The choice is limited when it comes to screen sizes for both which can be an issue although LCD's are being offered in the larger sizes now. When you bought a CRT Tv you expected it to last for years, which they did, So when I upgraded to a state of the art plasma the least I expected was an acceptable length of service.
£1850 paid and less than 2 years before developing a fault just ****** me off, reason for my rant by the way.
Just a quick update, a third vertical line has now appeared. I now have two green and one red line. Yipee! Can't wait for some blue line to appear so I'll have the full set. shouldn't be too long as Panasonic are quite reliable they say.