Your TV is a 2008 model and I can tell you that, the particular panel connect technology used during that time frame (e.g. tabs), has been prone to failure in numerous brands.
No doubt that Samsung gets a bad rap, because they by a wide margin, just sell more HDTV than anyone else.
Actually, I own a Mercedes Benz; that used similar tab bonding in the instrument cluster digital display , that failed within 4 years, in nearly every car they built.
Mercedes has not recognized the problem, nor would I foresee one for your issue.
From the symptoms, doubt it's a power board or panel issue.
Most likely would be a tab bonding, LVDS cable or TCON board.
Since you have researched in depth, you know how to test and fix problems in each.