Back on topic:

I don't think using a test source is the complete answer because I notice that each source has its own issue and CATV lip sync can vary from channel to channel. Movie channels are usually the most consistent.

For example, one could have a test video on a USB stick, but this will not correlate to cable box issues and playing the USB directly through the TV will be different than playing through the AVR, Blu-ray, or whatever. Some of the current AVR's are relatively "neutral" with lip sync. (meaning that they pass through whatever sync is presented to them)