I just arrived to a house with a 42LV4400 model. I found a trick though which may kill 2 birds with one stone.

Discrete Power Off= Unplugg the TV
Discrete Power On = Plug it back in

The TV must be on before you remove power, but when you plug it back in - it turns back on.

I am going to use an outlet switch from Control4 to turn the TV on/off. Im not sure if this will work after being unpliugged for hours or days, but ill keep testing.

And hopefully with all the power cycles, the TV just breaks and they can get a new set with discretes.