The Caddy WAS the recommended tow vehicle in the 60's. Suburbans have been the tow vehicle of choice for many years in the AS community. Ford did a real good job of offering options with the excursion and expedition, so now there is quite a mix.
The story goes like this:
At least once per International Rally the comm center gets a call from the children of a member. The kids do not know the WBBCI Number of the rig but want an urgent message to be sent to their parents. Invariably they say, "They are out there in a Silver Airstream towed by a blue suburban" That narrows it down to only 60% of the attendees.
On the picture I would bet it is a photoshopped negative that has been flipped and then melded onto the rear of the 'burb.