http://www.hobbycity.com/hobbycity/s...idproduct=5548 with a suitable powersupply (its DC only) would be your best bet, and no need for seperate balance plug adaptors as they're built into the charger. Something like
this would be ideal for the powersupply.
I would also go for the 25 or 30c turnigy packs over the 20c- a little more expensive but well worth it for peace of mind.
The 8 cell version of that charger looks alright, and with a suitable powersupply it would be able to charge two packs at once, but the required charging harness (that one linked to isnt quite right) is a custom job & a half, though BrianG has diagrams on his ScriptAsylum website.
For the money, it would be easier to just buy a pair of the 6s chargers and powersupplys, if you want to charge up multilpe packs at once...