That sounds like a good idea actually... although half the stuff you said went over my head (source current dropout?
)
I checked out the transformer, 15lbs is quite heavy, but it's not moving anywhere, who cares I guess. IF this were to be used I might want to get the BMS then as I takes care of balancing while being charged. 10amp charge sounds really nice, as it will be charged on a 720i at about 9amps, each side, so you have to do that twice. Looking for a dual output charger that can charge 7 cell packs... why not a 710i DUO, Hyperion?
Also, for another idea for emergency charging, say you are away from your charger and don't want to use your own effort to bike back (far away), I was thinking a small charging circuit built into the battery case. I was thinking just a couple amps at the most with a built in AC socket with protective rubber plug with a PC AC cord somewhere on the bike stored away.