I'm not sure if they still offer them but I have a 2010 Dodge Cummins 3/4T mega-cab. I needed a diesel due to buying a heavier trailer than my 1/2 ton Suburban was happy with. I really wanted a 3/4T diesel suburban but they quit making those a long time ago. My neighbor had a 2008 Dodge 1T diesel mega-cab and I tried it out to see if it fit in my garage-it did. And, I could fold the back seat flat and fit a large and medium kennel in side by side facing the door.
It is the closest thing you could buy to a diesel SUV as far as interior volume went. I can actually get 3 kennels in but then you have to let one dog out, then remove the kennel to let the other two dogs out.
I've been hunting with it five seasons now. If I take 3 dogs, one kennel has to go in the back in the shell, with an insulation cover on the kennel.
One drawback to a pickup with shell vs a big SUV is dust entry in the back. I've used a variety of purchased and home fabbed tailgate seals, all with problems when driving around all day on gravel roads.
Let me know if you need dimensions or pics.
Tom