I thinking of this as an Off-Loader solution. Look at page 85 of the HVX200 manual to ead about how to verify the data transfer from P2 to Firewire drive.
Well, there is already a solution for this… It’s called the P2 Store. It unloads and reformats the P2 Card in one go. It’s the most efficient solution. I would never consider the iPod as a viable solution. The existing battery would be sucked dry in less than an hour. And the hardrives are slow. You’ll be waiting for very slow transfer times as compared to a 3.5″ external 7200RPM drive. And to top it off, I would feel confident with my HD content on there. I have two iPods and I think there amazing music players, but I have often had to reboot them. I believe the HVX200 also has a transfer of data check which looks at the Data that was just transfered to validate it before you format the P2. This would furthure kill the iPod battery very quickly and longer waits before shooting again. My plan of attack is to use a small battery pack (https://www.preparedwithpower.com/portable/) and a rugged external Hardrive to offload. Sure it’s a little bulkier than an iPod but it’s failsafe and I don’t need to carry around a laptop either.