The thing you must do is stop thinking about what is good for SEO or not. The goal of yours is to get sales or rented whatever so think think about your customers solely. What will be good for them, what will be liked by them or not.
In my opinion. You should have separate site structure but also have soft landing pages for each product. Linking should be a priority here. After renting or buying one product the users will search for related products and what not's so your pages should be optimized in way to represent those.
The best thing here to do is create a rough site structure with landing pages and all. And then create a survey for it. See how it goes with actual people. Make changes accordingly. In this type of sites user experience is all.
In my opinion. You should have separate site structure but also have soft landing pages for each product. Linking should be a priority here. After renting or buying one product the users will search for related products and what not's so your pages should be optimized in way to represent those.
The best thing here to do is create a rough site structure with landing pages and all. And then create a survey for it. See how it goes with actual people. Make changes accordingly. In this type of sites user experience is all.