Ah yeah, that is somewhat akin to the SATA data lines inside my PC come to think of it. I guess that is actually a full size SATA data port then. You could buy a cheap PC PSU and run it outside of a case, just feeding the SATA power lines to the drive you have connected. I can't find a USB to SATA power adaptor that just uses the USB 5V lines, so I guess using a PSU would be the most practical way to do it. And even then, I've not found any of my 3.5" drives actually spin up on USB 5V/2A power alone but with a 60W PSU and up, that shouldn't be a problem. Just avoid feeding any paperclips into the ventilation holes and you'll be fine.