My '12 Caravan has the spare under the chassis too. It has a big lug nut under the front console that you turn with the lug wrench and it lowers the tire down so you have to get under the car to drag it out.
The '95 Dodge Ram 2500 I had (before my current '09 Dodge Ram) had the same setup, only the access for lowering the spare was through a body panel below the tailgate.
We were driving on the freeway one day when a car pulled up on my left and pointed to the back of the truck. I pulled over onto the shoulder and stopped, got out to see what the problem was. Evidently the cable on the lowering system had rusted through and the spare had dropped to the roadway. The previous owner of the truck had installed a cable and lock to keep the spare tire from being stolen. That cable was still intact and we'd been towing the spare tire/wheel behind us. How far? Don't know but the still new spare tire now had a nice 3" hole worn through the sidewall from being dragged.