For those of you considering bank charging I just stumbled across a single unit bank charger at a reasonable price from a known manufacturer. It's switchable and can handle up to 6 batteries:
It's comparable in price to buying 5 Vectrix chargers - and cheaper than buying 6 (although many folks will be charging a 60V system so won't need that capability).
I just bought Don "I'm doing it by the book" Cristobal's chargers so I'm all set. Otherwise I would have gone this route instead. I still might.