This is really interesting and not something I was aware of. (Although now the fact that an hour of MiniDV footage is 12GB makes more sense!).

I wonder if this is what DV Rescue (linked in my above post) is doing? If it's not doing this, it's certainly something that it should be doing.

You're also 100% spot on with the idea of using different drives to recover "tricky" tapes - I have two MiniDV camcorders exactly for that purpose. But I was doing it the "long" way of trying a tape in one, and if it didn't work well, trying it in the other. It didn't occur to me that I could try combining the results of both.