20s?? Sure, HV is good, but there's gotta be a point where the pack just gets too big to be practical.
My 2 10S A123 weighs as much as my 2 5S 4600mAh TP extreme (long version) packs. Plus you can save more weight and space if you go with the Bosch 36V packs. Here is a picture of the small 36V pack: http://www.rc-monster.com/forum/show...3&postcount=20. Plus with 20S all you would need is those small 2200mAh cells.