A crazy idea: 
Is it thinkable to use a smpte TC audiotrack from a HDV recording to sync a multicam recording? I was thinking of sending smpte timecode audio to each camera (different brands) in the setup during recording (can be done with cheap wireless systems) and then sync them (with some sort of script) in the NLE using this audio. The reason is that I can stop and start a camera when I want to save tapetime on certain camera positions. Normally I sync them on a flash or with the original audio. But when there are gaps its hard to line them up each time again...