You should be able to do that with an adapter. And if you use usb for headphones (which by the way is just ludicrous) you already live the dongle-life. Though

You should be able to do that with an adapter. And if you use usb for headphones (which by the way is just ludicrous) you already live the dongle-life. Though the motorola Z phones has what you want. Add the turbopower mod and you get the powerpack and an additional usb connection that can be used for charging (not sure if that mod allows that usb-port for anything else), leaving the original unused. The Z-line is also the closest you can get to a replaceable battery so that is pretty neat as well.