A 14 year old kid did this.
Thank goodness for getting lost. I was looking for an address when I saw the owner of this rig pull up onto his driveway. I had to investigate.
First, the young man was shocked that I knew this was an Isuzu Trooper. He performed the conversion when he was 14. I asked him how long the process took. He replied-- "Who knows. I was 14 and couldn't drive so I had plenty of spare time." Torsional rigidity was not compromised too much with the help of the rollbar and the spare tire holder welded to the back.
The owner's friend had a similar conversion project but had less luck with a Sawzall. Said friend lopped off the entire roof (along with the B-pillar). That vehicle essentially collapsed onto itself after a bit of driving, like a black hole!
The Trooper's owner told me that he's going to make this four cylinder truck "bigger".
Me: Like, are you going to put bigger tires on it?
Him: Nah, I'm gonna drop a Cummins diesel in it.