What size Trayback?

Thanks for the replies guys, pretty much as I thought. Looks like it will be a King Cab........

Might sound like a dumb question Spitster, but why can't it be a single cab?
If you have a carry me camper than you already have a tonne of storage space. That is one of the fundamental reasons for buying & carrying one around.
The single cab will carry the 400 plus kg of the bare camper far better than a kingcab or a dualcab as well because you will get your load centre closer to the rear axle.
A single cab will cost you much less as well.

Just not comfortable with the lack of room in a single cab, I am a big bloke and need to have the seat right back and whilst travelling need a bit of extra room for camera gear, laptops, drinks, food and other bits and pieces. Can get quite cramped in a single cab and for a mildly claustophobic big bloke the king cab ticks the extra boxes.

If you are a big bloke & need room you better look at a Patrol or cruiser ute.
Hilux might be OK but Triton & Navara & Colorado are definite No No's if you are as big as a bloke that calls himself Fatso.
I reckon the doors jams on the Triton, Navara & Colorado are to close to the seat & you have to cramp up to much to get in & out. It's OK though if you don't mind boot scrapes on your door.
With Landrover the drivers seat is to close to the door. OK if you are a little bloke or drive with the window down so you can hang the arm out that doesn't fit in.
Check the head height as you get in & out as well. Being able to get in & out with a hat on is a good indicator.
The Patrol & the Cruiser are head & shoulders above the others. Bigger higher & wider seats & a full size centre console plus real headroom. Can't beat them, unless of course you get a yank tank.

Thanks for the feedback Fatso, however I am long not wide. I currently have a GU Patrol wagon, and have test driven both the Patrol and Landcrusier ute. Also have spent a fair bit of time in a Navara D40 (work vehicle) dual cab and their is just as much room on one of these for the driver than a Patrol. If Landcruiser or Patrol made an extra cab, would solve all the issues. A big rugged bush ready vehicle designed to go just about anywhere straight off the showroom floor. But like all things in life, we just have to compromise, unless you want to spend the 15K on extending one of these utes. Then doesnt fit in your garage or any car spaces.