Yup. You could do that to get the car running. You'd still need a couple of 4-cell packs though.
As for the pit spaces, hopefully Chris can find the time to make the shelving that he mentioned, then space won't be an issue. Believe it or not, I bring less stuff to Xtreme than an average racer would bring to a track. I don't even bring a tweak board, set up station, etc etc