For folks that haven't ridden in one: they've got a gigantic hump in the middle for the 4WD transfer case, so the actual seats (they only seat 4, BTW) aren't much bigger than the ones in my Miata.
I mean, we're talking about doing a full teardown here. The shocks are going, the engine's going, the seats are going, basically everything except the frame, wheels, and maaaaybe transmission is gonna get thrown out.
Listen, I can dream okay lol? Also I have no illusions about it being a hell of a lot of work, it also wouldn't be my first car. There are other cars I'm more interested in; doing a humvee overhaul like that would be a "I have lots of time and money" thing.
It's not being engineered from the ground-up; these are all common modifications in the car guy world. The only semi-complex part will be getting the suspension custom-valved if there's not something already available on the market for daily driving, and even that is fairly doable.
Adapting comfortable seats is a straightforward process; adding noise dampening and carpet is a straightforward process (good noise dampening material can turn almost any rattle box into something really close to if not equal to a Lexus in terms of noise). Exhausts are not voodoo, resonators and mufflers are available for virtually any conceivable application... etc
What I would wish them good luck with is not running out of steam to get it to where they want it.