Can we discuss pros & cons re gas or diesel? We're still looking at Bs. Some are gas, some diesel. We don't like the higher $/gal of diesel because it would offset any real savings from the higher mpg...
As far as I have proved, if the OP is looking at new vans, on dealer lots (I assume as he indicated they are out looking at vans), then the answer holds that it's not available. Not available for order either as far as I can tell.
If the OP is looking to buy used, then the answer is maybe you can find and old one. They are a very rare beast.
If the OP is looking to commission a custom built, new rig, then the answer is, maybe, if Sportsmobile will do it for you.