Can't see much point really in the e van.
With the good economy we have now with 26 mpg(us gal) about 30 uk gal it's not worth the hassle.
What I would like is to have electric assist on my big Chevy express 1500. If a double or tripple regular battery set up could boost the off the line fuel economy so it does not suck gas getting moving I think it might improve the 12 mpg I get now .....but they will have to test that first. They do have a Trans with a electric motor assist on the side already made.
But that's a different van for a different forum
Right now I really like my 26 mpg and about $25 to fill up to go the same distance that the big van takes $70 to do.