Why not just make a tent room off the back of your existing shell? Use the bed of the truck as the sleeping area, and a stand up tent room off the back. I used to do basically the same thing, I had a $40 screen room that I would set up off the back of my truck.
My set up was obviously pretty crude, but it worked surprisingly well to keep bugs out (when the zipper was closed), and a fair amount of weather protection. A custom enclosure that is freestanding/not dependent on the vehicle that meets your wife's needs would be an easier solution IMO. Using the bed of the truck as the sleeping area worked great for us, it was truly weather proof, no matter how bad it got outside the sleeping area wasn't going to collapse from the wind or start leaking.
I'm in your area, high profile tents and the desert winds that we get can make for some miserable conditions. Not sure that your conduit plan is going to have the strength to hold up.
Coan Racing/Dust Junkies Racing, 2012 Baja 1000 Class 1700 Champs
Dust Junkies Racing/Fat City Racing, 2010 Baja 1000 Class 1700 Champs
Fat City Racing/Dust Junkies Racing, 2009 Baja 1000 Class 1700 Champs