Sounds like a fun project. I'll be eager to see some pictures.
How will the the differences in body configuration affect the handling with the C-4 suspension? Instead of a very low body, keeping all the weight real low, this panel/Suburban will have much of its weight higher than the roof on the donor car...
I found a C-4 available for $500 recently and am tempted by that suspension. Its too far gone to temp me to rebuild it.