AK campers is bringing the second flatbed ever made by AK to the Overland Expo in Flagstaff. It will be a 8 1/2 ft long on his truck. Mine is 7 ft. His flatbed was made by Protech a great aluminum company for boxes and beds. I couldn't afford one so we made our own here with steel but it was still a light weight design with protech boxes. Their boxes are made well and seal well.
Aww yes diesel was in our thoughts, liked it for sure... but a long story short after talking to diesel mechanics and I don't tow heavy things, no need to rush, and we may put the truck on a boat to somewhere where diesel is like chicken grease, I choose a gasser. lol
An update: with regards to rain/water. I have not had any water get in while driving through rain and snow at highway speeds. What has occurred is bug splatter(as usual) on the outside of the cabover. When it is on the sides(see pics) and you raise it up to make the overhead bed it sticks and is on the inside when bed is made. I wipe off the bug splatter (easy) now that it is on the inside and all ok.
I choose to have as few as possible outside storage cutouts. So the camper is well insulated for cold or hot weather camping. We use a solar shower. There are 2 outside access doors with a little room in the fridge and propane bottle areas. I am going to build a bracket and bolt an outside tool box in the rear that will be removable. It can hold more stuff, extra fuel, water, folding stairs, inflatable kayaks, long items etc. If I had a longer truck the under bed tool boxes would be longer and hold the folding stairs. I also installed a front receiver hitch so we can put the mtn. bikes on front or back. There is more than enuf storage for us with the camper and boxes under the flatbed to get all outside items in their place when we plan a long trip taking it all.
Love the Yukon and Whitehorse area maybe next year. We were up in the are and on the Tatshensheni July 2017.