People in the US want them
People here don’t
So rather than a manufacturer having a production line banging them out Henry Ford style you’re looking at a company building it more like a Morgan, hence the higher cost.
The Iveco will be a pain to take into any busy car parks, the 5th wheeler will be a pain to park anywhere.
I’d suggest a bus, towing a trailer with a 4WD on it.
If you really want the 5th wheel style spend $10k on this, rip out the chiller unit and build some windows doors and walls.
http://www.trucksales.com.au/buy/privat … &pss=Price

Then go and buy something that’s really and truly intended to tow a trailer that big, Mack and Kenworth are pricey options – I’d suggest looking at Volvos. Get something with X locks and air bag suspension.
Get something that has space to add an extra seat, it’s common to do in trucks that are used for driver training.
If you don’t feel that you’re capable of getting a semi license you really shouldn’t be setting off with a 38′ 5th wheeler behind a light truck