Just an idea to make a dual cell with out the second cell, we could use a regulator. I have a few of these ones which i think will work,
Look for the 'TPS61015'. They are really small and could easily fit into a Bit. Of corse there would need to be other components but if we did it surface mount we could keep it really small. The PCB would just go inline between the battery and the RF board it would mount on top of the RF board. The increased voltage would also be able to operate a small PICmicro which would be able to control LEDs for headlamps, you would be able to program it so when you pressed forward twice then the front lamps come on etc. I also have a few PIC 12f675s that could do this job, they are also surface mount just to be small!