Here is a link from a forum i frequent..Its definitely doable but im wondering how tall you would be in the end.One of the benefits of a uhual is the are lower..Im thinking of building a stepvan right now thats got a height of 10ft..If you go higher towards the 13ish ft range then you will have to take a trucking route everywhere you go..That can jam you up sometimes.Just keep going further back in that section of pirate and you will see a few builds from uhauls..Just have thick skin if you post.
http://www.pirate4x4.com/forum...wthread.php?t=691445
Im thinking of building a pop up tent to have a loft in my conversion.I have seen some rooftop 4x4 tents but they are costly and not totally what i need.Im gonna start looking at the pop up sections of the newer truck camper pop ups as well as a regular pop up..When its down i want only to 18" of extra roof height.Wosrt comes to worse i will build it and have the canvas built for the sides at a boat shop.I just need some extra bed space for the kids when we are at off road parks.
I wouldnt put a water tank up that high..You can always get some 16 gallon drums from craigslist opr someplace and mount them below the body..use an on demand pump for supply.