Cool looking little buses, but the rear axle is the weak link. The conversion companies (there were several building micro-minis on toy truck chassis) bought the cheapest, strippedest chassis cabs they could get from toyota, then built a camper on the back. suspension upgrades would include air shocks or an add-a-leaf. toyota finally had to quit selling the chassis because they kept breaking axles off and loosing wheels and flipping over and killing people, etc....
The fix is a full-floating Cruiser axle, only found in USA spec 1-ton duallie minitruck chassis.
I did the research thinking of buying one of these a couple years ago.
Google "toyota camper conversion rear axle" or something, to find lots more info.