> They could’ve done something like the Slate truck a decade earlier.

They could have Roadstered it.

Buy Ford Transit 350 "gliders", work out how to make them FWD, RWD, or AWD using your own transaxles and batteries. Pickup, van, or just a bare chassis-cab to go to a coachbuilder, it doesn't matter.

The Transit has been around for 61 years. Sticking electric motors in it that you already have is a no-brainer.