Using A123 LiFe batteries for now about 6 years as receiver batterie on single or dual power systems, ignitions and lights, I just want to give you an update on actual alternatives.
LiFe cells from Engel Modellbau , rectangular packs with MPX plug, balancer plug EHR, 6,6V, 850, 1450,1700, 2100, 3000, 3800 mAh
LiFe cells from Hacker, rectangular packs , no plug, balancer plug Thunderpower, 6,6V, 600, 1300, 2100, 4100 mAh
These cells are also available with 9,9V , 13,2V, 16,5V (ie 3, 4, 5 cells, 30C)
LiIon cells from iRC electronic, single cells, kit, or ready packs 7,2V, MPX or Grp plug, EHR balacer plug, 2900, 5800mAh
LiIon cells from Jeti Model, single cells or ready packs, MPX load plug+Grp charge plug, 7,2V, 2600, 2900, 5200, 5800 mAh
Duralite LiIons, Magnum ION and LiFeO, A123 cell packs in different configuration, internal or external balance, 6,6V or 7,4V, 2100-7800mAH
check website for detailed information
Powerbox Systems Life pack, MPX plug, 6,6V 3200mAh
All these batteries, there are other manufacturer's, are a not explosive and inflammable like LiPo batteries.