Matt,
Take a Look at Fromeco http://www.fromeco.org/

2600Mah RX 2 cell packs for about $30

Pull pin switch regulators

Cool multiple output charger

and now a new dual fail safe battery switch called a Wolverine.

I have been told safer than the duralites, but who knows, a lot of people are using these in this area and they are real popular with the big gassers.

BC