I think whichever you end up with, will get used well. After going from a Full Size Jeep Grand Wagoneer, to a Suburban, I find that after loading, I still have the same amount of room left!
I think the idea is that however much room in the rear you have, you will use. I was just as comfortable going out in the Jeep as I am in the Suburban, although the Suburban allows us to sleep inside comfortably, while in the Jeep, we tented. It wasn't necessary, but the Sub has tinted rear windows, so there is no need for curtains. My Jeep had very clear glass, and I never got around to making any curtains.
Good luck with whatever you choose. I kind of dig the Diesel Excursion idea
Clay