Does anyone make an aftermarket external power grip for the M10 or M10-R?
You pull off the baseplate, pop the battery and the contacts are right there. External flash battery makers do this all the time for flashes without external power contacts. For the M10-R there are your basic aftermarket grips, and I would think it would be a pretty easy thing to do a power grip with slots for two batteries.
(I'm a former analog / mixed-signal IC designer - fast A/D converter, Ethernet LAN media interface/analog signal synthesizer, battery gas gauge designer with 25 years in Silicon Valley - so I have an informed opinion / expertise in electronic design.)
Thanks.