i was wondering about the power usage of these extensions, do you have any measures of those? my intuition was that the microSD would consume _way_ more than the 32MB flash, but can't imagine how much any of these would take on top of the base usage....
also for -30 (here in Berlin we used to reach -20, but unsure if this will ever happen again) i think we will need a different type of batteries than LiPo or LiIon... Sodium-Ion seems to be a good candidate...