New Rv Shade screen and Add a drawer for more space

Here's a thought. If you can't find anything else try contacting someone that makes boat covers (any place that sells boats will have names). I bet the screening you're looking for is readily available at home improvement stores. Someone that sews canvass will have machines to handle the material. Also auto upholstry shops.
You'll just have to show them how you want to attach it, so they can sew your attachment right into it and finish off any edges.