I am familiar with the concept that
@Grapehound is addressing. I have thought about doing something similar to this as an informal list.
The problem becomes the quality of the experience. In the past, GoodSams was a club that was just for the purpose described above. A good sam was a volunteer willing to help out where possible. In 2005 I broke down on the Katy Freeway with a pickup truck towing a 5th wheel. We sat on the side of the road for 2 hours trying to get a tow truck or any resolution. I called my Roadside assistance (can't remember which one) and was on the "waiting list" for a return.
I pickup truck pulled up with a retired marine at the wheel. He said he was a "good sam" and lived nearby. We got to talking to him and he was willing to tow my 5th wheel the 20 miles to the park, had his wife come get the wife and 4 kids in her car, and got everything setup for me. He refused any kind of payment, and said that is what good sam used to be, and what it will always be for him.
The organization today of Good Sam is nothing like the original. Looking at the many challenges for "corporate" sponsorship, I see that the need to protect ones bottom line and insure against any mal practice etc is the top of the reason we don't see this today.
Not that it can't be done, but things to consider:
* Who is going to vet the qualifications of the driver? A person that has driven a class C 24ft isn't experienced in what a 45ft Diesel pusher drives like. The same is true for a person that drives a 45ft motorhome, they aren't experienced with a 45ft 5th wheel.
* How do you handle a situation where a good samaritan becomes involved in an accident--regardless of fault?
* How do you handle the "fair" pricing?
Many other issues that make this complicated. I would love to get this going, but it is not an easy task.