Lcd Mounting Arm LCD/Plasma Extended Arm Mount?

LCD/Plasma Extended Arm Mount? - lcd mounting arm

I want to ride 52 "LCD or plasma TV in front of my terrible corner. The arm must be at least 26" from the wall. I have the double line, the arm supports 27 and 28 "but I wonder how safe it is fully extended? I think a little, but nobody has done that SAG, I thought the line side wall of the niche, but safer. ideas? you can not in the American context, because it is a rental.