Nice job! I don't see this as being any more or less convenient than rowhard's "space-saving" design; both have advantages and disadvantages. rowhard's design preserves more horizontal floor space but does so at the cost of vertical space that might have been used for carrying wider/taller cargo that needs to lean over sideways to fit. Navistar's design eats more horizontal floor space but let's you use the full width of the cargo space that remains. There's no question that rowhard's solution cuts visibility (just look at the pics) but whatever is lost can be regained with $3 blind-spot mirrors. Both are great alternatives and honestly I don't know which one I'd choose.
Pics for comparison: