I'm not the guy to do the calculations but I'd bet you would need to reinforce the slot your taking out of the hull tube similar to the way you have to reinforce around a viewport. The forces in the hull tube would be trying to close your slot and would have to be carried across the opening with something substantial. More then just the ribs in that area.
Also, with the batteries in a box like that you would loose the protection in case of a battery explosion. The way it is now, the pod end cap will blow off but you won't flood or get hit. But, Maybe battery explosions aren't such a big problem as I was led to believe.