It happened a second time about a half hour later, though I also noticed that the DVD player/surround sound unit also went into standby at the same time. When I turned the TV back on, the input changed from the one I was running cable off of to the one used for the sound system.
I had the cable box sitting on-top of the sound system (which has no top vents), the top of the sound system box felt pretty warm. I unplugged power to the sound system, leaving only the cable box on for an hour and experienced no further problems. I then moved the cable box off of the sound box and plugged it back in for another hour or so with no issues.
I figured that since the surround sound box automatically changes your input to it, that maybe it has the power to turn off the TV also. Does this sound logical to anyone?
My set is only a little over a week old. Ran 100 hour break-in, and currently probably around 10-15 hours of TV/ movie watching. It was made in 2009, if that's what you were asking.