I would say if I were doing this I would sort and look at what I wanted to store in the closet and then look around at closet systems and see what fits my needs at the cheapest price. Most of them can be configured several ways. If you don't have a lot of dresses or long things maybe you only need a short rack for them, on the other hand if you store slacks on slack hangers maybe you want a longer rod. Maybe you have a lot of short things so you may want 2 rods. Maybe you have lots of shoes and need shoe storage. Maybe you have lots of sweaters that you like to fold on shelves. Only you can say what is going in there. It's useless to get a gorgeous closet organizer if it doesn't fit your needs,

Customizing your closet for you and your lifesytle is what you want to do. Assess first and then go shopping for the system that fits you.

Maybe a big box store or ikea have systems that would work for you. But first you have to know what's
going in the closet

We went through this six years ago when the covered wire we put up just to have a place to hang our clothes when we moved in fell down.
If you are talking ec-O friendly when you wrote ec-I friendly than my suggestion is so so. We built our own closet using my layout plans with MDF real wood trim and rods along with standard closet hardware for holding up shelves and rods. We did it all for around three hundred dollars (if we remember right it was just under $300) and our closet is 6' by 14'.
Here's a couple pictures of it during the process. We starting putting clothes in so I never got final pictures.
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What length wall is the door of you closet on? I'd be happy to help you with a layout plan if you'd like. If you don't have a table saw or just a car to bring the MDF home with Home Depot will make the cuts for you. No cross cuts, but they can be done with a circular jig saw.