dl423:You should consider the fact that reliability can have an inverse relationship with complexity. It is possible for this circuit to fail in a manner that will cause a weak/dead battery to be selected... Wiring the batteries in parallel, possibly using diodes, is a simpler, more robust design.
I remember reading a disclaimer in a databook stating, to the effect, that that particular companies parts were not certified for use in applications where lives could be placed at risk and that any application of that type required written approval from the president of the company...
Thanks for researching the mfg info, good to know.