Cosmo,
I have to agree with Ashe on this. Horsepower really is very low on the list of things to consider for towing. Tow rating really is everything.
You are right, sometimes you have to dig to find the full answer on the tow vehicles. You mentioned the Caddy for instance. For years that is I what I had for a tow vehicle. It was listed at 1000lb, which was not enough. I just couldn't understand how a V8 car with that transaxle (4L80) could possibly have that low a tow rating. Much digging gave me an answer. There was a tow package available for that year. That tow package allowed the Caddy to tow 3750lb. What was in the tow package you ask? An additional tranny cooler and a oil cooler. Talking to a GM tech I found that the oil cooler was found to be a bad idea because of the engine's large oil capacity, the oil would not run warm enough. So, scratch that one. The tranny cooler we found was required if towing over 2500lb. I am towing 1500lb so I didn't have to do a thing to tow with the standard Caddy.
Another good example is the VWs. Alot of VWs have a 1000lb tow rating, which is just not enough. However, the VWs are built to meet the O1 towing standard in the EU. This standard requires a minimum 750kg (1650lb) rating. If you call a european VW dealer they will tell you the same car tows 750kg. So, it is a VW north america policy, not the design of the car.
For sure though, for towing the Camp-Inn we want to see a tow rating of 1500lb or higher. Vehicles like the Fit, Yaris, Scion and Soul just should not even be considered. You will likely have serious transaxle and other driveline issues towing with vehicles like this.
Of your list they all have very low tow ratings other that the Accord and Camry. Both of those have adequate tow ratings and we do see these being used towing Camp-Inns. We also see a few VW Beetles, for the above stated reasons. We also see a few PTs and HRRs. In those cases a super light option set on the trailer would be in order.
The Subaru Outback is clearly the most popular tow vehicle we see here. 30mpg+ for a late model. If a Outback is "too much vehicle" consider the Forrestor or the Crosstrek. I just got a fantastic towing report from a Oregon customer towing their 550 with a Crosstrek.
Cary