So, Rabid, you're saying these new cargo boxes:
~ would be up flush to the original JAMAS cargo boxes,
~ and open "outward", i.e. opening hinge would be down the middle, with each lid opening like "wings".....
~ and JAMAS says they'd be accessible by flipping seat forward.....
If I got that right: Here's some stuff to think about:
~I think you'd find you'd really want access to them from the back, especially because they'd be larger than the JAMAS I boxes, and items stored there may well be larger....drill, saw, wood, etc...??
~And it would be really difficult to reach OVER the JAMAS I boxes, to get to these.
~You'd be using all wrong body mechanics if you tried to lift anything heavy out of those boxes, while reaching over the first boxes.
~ You really wouldn't be able to easily access the opening lid, IF iT'S as currently described. Now I'm only 5'5", and most all of you are way taller than me, but I had a hard time reaching OVER my boxes, to get to cargo I put there. For my Moab trip....it was a lawn chair, tool bag, 2 plastic tote bins about 30" x 24", a soft sided cooler and roof rails () Most of that stuff was NOT accessible via the door and moving seat forward.
~ If the boxes did NOT go all the way to the back boxes, and mainly were as Eric mentioned, for behind the fronts seat area, it would be more manageable IMHO.
Just my 2 cents after using the JAMAS I boxes.
BTW- I wouldn't change a thing on mine, they're great!