I agree, it'd be a very useful troubleshooting tactic.. but one I'd rather prevent, as the issue can sometimes take days to reproduce in addition to the fact that my wife loves the DVR.
The EDID info in the Diagnostics menu shows that the TV is capable of 1080p60 when the issue is currently active.. am unsure whether this eliminates the TV but it makes me feel more strongly it is the box, for better or for worse.