At the 2013 International Builders’ Show in Las Vegas, Panasonic had their new line of Tough IP(TM) power tools on display.
Some tools in the line will feature dual voltage technology, whereby you can swap out the 14.4 volt battery for an 18 volt battery and gain added performance. They can use either the new Panasonic 4.2Ah LS Li-ion battery pack (yes, 4.2 A-h is a lot), or you can use existing 18 and 14.4 Li-ion batteries. See full specs here.
See press release