Caleb,
Are you taking about making a one off model and then selling it as a completed project to someone who has no interest in building something themselves? Because if that’s what your talking about then that is a hugely wide open and, in my opinion, un-answerable question. First off how good are the models. While I think I am a decent enough modeler and like what I build I wouldn’t pay much for it. But if I were to buy one of Ray’s buildings well then that is a whole different ball game. It would depend on if your building a Bachmann Annie or an Accucraft Live Steamer 2-6-0. Then you have to figure its worth only what someone will pay for it. Making a model that no one wants no matter how fine the craftsmanship is not going to fetch a penny, whereas making only a decent model of something that is highly desirable might fetch a price that out values its craftsmanship.
I have found this out in wood working. I turned a very beautiful live edge bowl that I thought might get me a few bucks at a garage sale, no one even offered to talk me down off the $40.00 was asking even though I saw lesser bowls asking far more in galleries. But I made a redwood bench table thing that I sold 10 of for $150.00 bucks each. No where near the skill required but it was more desirable so people bought them. So I don’t know that it would be easy to say $100 and inch. Model ships have a following and therefore can have an anticipated draw.
The market and the consumer will set the price that I promise you.