im not sure if the HVx formats its P2 cards in FAT32, but this solution would be pretty neat as it allows for dumping via USB to unlimited little portable USB2.0 HDDs vs a USB OTG HDD which are cheaper than USB OTG HDDs. possibly even provide power for them over USB. anyhow, i thought it (and similar USB OTG bridge devices) was worth a look.
http://reviews.cnet.com/Sima_Hitch_USB_Transfer_Device/4505-3335_7-31997849.html
http://reviews.cnet.com/Sima_Hitch_USB_Transfer_Device/4505-3335_7-31997849.html