Just for discussion's sake, here are pics of my Xterra and a buddy's Escalade loaded out for post-katrina Mississippi. You won't have all the radio gear, but this'll make you think about that it'll look like loaded. The back seat is down, so the entire back deck is used.
Leaving for Mississippi

Steve's truck on-site. Note the raised platform with bottled water underneath it.
Steve's truck

I'm strongly considering one of the Silverado Hybrids for my next truck. It'll be several years yet, so we can see how fuel efficiency develops.