You could do six 12V chargers - two 6V batteries per charger.
I use six BMSBattery.com chargers - the 240W allow shell ones. I am very impressed by them - they pump out 10A right till cutoff at 14.8V, where they hold for about 15 minutes before switching to a 13.8V float.
Here are the details in my build thread when I first got them:
http://ecomodder.com/forum/showthrea...tml#post350615