aapezzuto, good luck with the babies. It is a long time to lay in bed. I hope she has enough to read.
The idea of parallel batteries is a new one to me. Usually the batteries are chosen to provide the right level for the logic in the reader. One cell give about 1.5 volts so, for example the old Palms use two celsl to achieve 3 V. This method would entail having twice the number of batteries thus twice the weight. Alternatively they might use a charge pump circuit to enable use of only one cell. Interesting idea. I suspect though, that using one battery at a time vs using both at once will give you the same amount of reading time.
I prefer to be able to replace common AAA cells, and to use rechargables if I wish.
As for backlighting vs eInk and a lamp, my accommodating Chinese wife doesn't mind if I use a lamp to read in bed. She says, "You like? You do." I think that is the best solution
