I don't think I'm going to run an aux tank on this truck. Better economy and 52 gallons is probably good enough for my taste, so I'm going to aim for a clean flatbed.
I don't know for certain yet if 18*18 underbody boxes will fit well but I'm hoping so. If they do, I've got a wide range of options. It looks like a 24" would fit behind the drives and a 36" in front. If I put all 4 on, that would be wildly more storage than I have now with a single tool box. I'm sure I could find more than enough crap to fill it.
I've priced out a few options, raw aluminum diamondplate would be a bit over a grand, and about 150#. I could get black steel off the shelf at TSC for $760 and just under 300#. There are some full stainless, and stainless-doored steel options too, around the weight of steel and around the price of aluminum. It'd be nice to find a Bawer, RCI, and Buyers dealer local so I could go touch 'em and compare to the TSC steel.
The weight isn't as much of a difference as I expected, but it'd be nice to have them stay looking nice for a couple years and I think that takes full steel off the table in this neighborhood.