The "correct" mod would be to place lithium ion batteries on the floor. That will allow space for larger battery packs, and promote safety at the same time. The "skateboard" configuration is inherently safer, because the battery enhances lateral rigidity. Of course, such a mod would have to come from Toyota. Any aftermarket conversion will be constrained by the fact that the vehicle was originally designed to host an internal combustion engine up front. I think Toyota can create a "70 Series like" truck that can be sold as a global vehicle.
Of course, Toyota can do lots of things, but somehow the U.S. always ends up getting the soccer mom models.