The reference above (FitRV's choice) is the best I've seen to date for commercially-produced rear door and slider door screens. Pricey, but there's a boat-load of labor that goes into making each one. About USD$650 each with tax (shipping probably more).
But you also asked about AWNING screens. I did a lot of research on that last year and I could not find anything suitable for a Class B. Those that would potentially fit the awning did not pack down to a suitably small size to carry in a limited space. So I designed and sewed a simple one myself (blog post here
). It was a lot of work, but very little money. No-see-um netting is actually very cheap.