Does anyone know if something like this will work?
Plug in a Lightning – camera connection kit,
Plug in a USB Y adapter, something like this.
Plug the red usb plug above into a suitable power adapter.
Plug the mini USB into a hub which will then be used with tried and tested usb devices.
Incidentally, Keith McMillen Instruments sells a device that does something similar to this, but it has micro usb, and I’d rather avoid yet another adapter. That and it is a bit pricey if you ask me.
via Can I hook up a USB hub and power an iPad 4 via the camera connection kit [simultaneously]? : ipad.