Personally, I see the possibilities limitless. When I was looking for a coach, we decided what we wanted (brand, model, year range) and looked all around the country on the Internet. Found about a half dozen that looked like what we wanted and narrowed it down to the best two. One was at a dealer (Tom Raper) in Indiana and the other was a private owner in southern Missouri. In the Tom Raper area, I suspected I couldn't find an inspector because everyone was either working for an RV concern or had to live there and wouldn't be very forthcoming anyway. In Missouri, this guy was so far out in the sticks, I eventually had to get there in a Cessna. No kidding. Bottom line: I couldn't find an independent inspector in (or who would go to) either location. I would have paid airfare and expenses.... not CRAZY prices, mind you... but a healthy price for a very well qualified inspector to fly in, spend several hours looking/testing and provide a written report with pictures... much like home inspectors provide for the real estate sales process. My target price? Probably between 2 and 4k for a top notch job. Like home inspectors in real estate... they usually ending up saving more than they cost... I don't think 5k is out of the realm of possibility for an independent and very well qualified inspector in the middle of coach purchase negotiations.
So, yes... I would have paid but, frankly, an online course educated inspector wouldn't even get a phone call from me unless that's where he started and now had 20 years under his belt. As a consumer of such services, I'd like to see a website with a resume and good reviews from lots of satisfied customers that have made it to external websites, as a minimum.
Good luck with your endeavor.
Edit added: If you haven't seen real estate home inspector reports... there are software versions that make reporting much easier than having to sit down and compose. Most have categories, check boxes and text boxes for additional info. These examples, I believe, could be used to rather easily develop your report template for RVs. And the pictures are key. You can't have too many pictures! In my opinion, a few additional pics are good but what's important are the deficiencies.
Again, good luck. I hope you put this together.