Help find Tow Vehicle large family 9 with seating for 12 min

Interesting need. It will be very hard to fill. What comes to mind are the smaller size transit buses. They are purchased as a chassis/cab and then the body is added by an upfitter. They would carry the number of people and come equipped with diesel engines. They are probably available on one ton or larger chassis.

These vehicles probably do not have a tow rating since they are not standard built but could still tow.