It is possible for a cracked panel to cause this effect, however it is extremely rare on plasma displays and the bar will usually travel in both directions of the screen (like an LCD.) This only happens when the damage is very minor, such as a little too much pressure applied to the screen. In most cases cracking the screen causes no picture whatsoever.
What the company may be confusing you over is that in most cases, a vertical bar does require a new panel because it is a panel level failure. I am not sure why they think $1,200 is a reasonable price given the age of the TV, unless you're talking about a 60"+ panel but even then it's too expensive.
Last edited by tom669; 07-03-2014 at 01:08 PM.