I found a 12v to 2x USB charger module on a popular auction site. It is a perfect fit for the dash blanking plate beside the cubby, near the gear stick on my Australian delivered GT 86
The cover and printing are not quite up to factory quality, But it's way better looking than any other solution I've come up with. I plan to take power from behind the console lighter socket.
http://www.ebay.com.au/itm/181705587332