Build a shield with a battery that can be charged wirelessly and conforms to the Wireless Power Consortium standard.  Many of the newer mobile phones have this feature built in and it will become the standard for charging devices.

I suggested that 3 days before you http://forum.tiny-circuits.com/index.php?topic=133.0, but, yes, I think It's a great feature and very useful in the mid-term in the upcoming wireless-charging scenario

Miguel Llorente