I think physics will limit his ambitions somewhat... and ADR's
It takes power to move stuff, so adding batteries to get extra range adds weight, which negatively effects your range, so you add batteries..... its vicious circle of diminishing returns and unless there is a lighter battery/vehicle, make it more streamlined or get a more efficient motor, then he'll hit the wall pretty quick.
Its a problem airliner designers face all the time, its relatively easy to make a plane to fly from Sydney to London, but after packing in enough fuel to do the job, you can't fit enough cargo or people to make it economically viable, hence why for a long time everything transited via Singapore or Dubai to refuel.
Pretty sure ADR's will have something to say about the vehicle and combined vehicle mass that may limit his ambition too. He might be able to engineer his way out of it, but a fully loaded Paj with a 4.5t trailer might push it into the medium truck bracket and need a licence upgrade for meer mortals to drive (not hard to get though). Pretty sure no Pajero's came from the factory approved for more than 3t.
Pumping a Paj up past the factory engineered weight limit is also asking stuff to break too. Reading the article he just wants it to go like stink for a short time, rather than long distance tourer, so he might be happy with 150km of mad skids.
Electric 4wd, how about a trailer plug to power electric wheels on the trailer, help tow in soft sand
Landrover did it with a PTO option, thats why the old Landies have that big hole in the rear crossmember