Bob - not knocking your post/opinion, very few TM systems that are in box vans won't fit in a sprinter, the monster reels you see on the v's and the like, you can make it work, but it wastes too much space leaving little remaining functional room, otherwise it's just planning old gear for a new layout, or replacing a few things, like the reel or some monster water tank.
I have apex d's with 100 gal waste tank, console fresh water tank, softener, 3 tier chem shelf, 4 custom shelves on the wall, 300' reel, block/tab/towel holders mounted, carry 2 wands, stair & uph tool, spinner, rotovac, steamer, repair bags, pad and tackless, dye kits, tool kit, and with all of that, could still have a dj and a 5 person dance party in my 170"ers. I still have room to put a porty if needed, cimex, and then some, a lot of some too.
I don't need to dot cert anyone, I get about 19ish fully loaded on average, unreal turning radius, easier to (well for employees anyway) and you can easily fetch a lightly used one for $30-35k with between 40k and 70k miles on them. Given that these vans will be still be going at 400k+, you'd have to be crazy to buy a new one imho.
Payments on a 30-35k note, $590 to $690 - gas I have saved per van per month going from box to sprinters, on the low end $380, the high $520, My cost of that van is now less than half of it's actual payment.
Sunday I pulled off a few of the non-water loss items, and fit 2 dehu's and 30 airmovers in one of my 170's, plus an extreme xtractor, 2 bins of resty tools, demo tools, and an air scrubber, neatly, organized, and still had more room if I really needed it.
I'm probably going to do one more box van, but it will be a sprinter box - solely for fire resty and packouts.
Everyone has their reasons for their van of choice, and I'm not bashing yours, just stating the reasons for mine, for me there is only one reason for a box, and it's fire resty, board ups, roof temps, and packouts. The regular sprinters fill every other need cleaning and water resty wise for me, (and maybe carrying the band gear...lol)