As much as love the M6 I am basically down to keeping one on the shelf with an MN15 and not using all my options.
I have a PHD-M6 pack, 3x17670 with outputs of 6.8, 7.4, 9.3, 10.8v, combined with this is an FM bipin socket - $185 for the pair.
Next up, 2 battery holders, a Petrev 6AA with...