Very nice! And, yeah, that would be easy enough to put a roof on. If you built a little 2X4 frame and attached the corrugated fiberglass to that you'd be able to put it on and remove it when you want.
As far as the plastic, it being ghetto was a huge concern for us as well. I love my Aunt dearly but her multiple chicken "coops" and runs are enough to make me cry. Her layout reminds me of the Winchester Mansion. She's got little makeshift chicken coops and packing crates and plywood "things" thrown together in a hurry all over the place. With those metal electric fence stakes shoved into the ground here and there with chicken wire wrapped around them and draped over top and everyhing all zip tied together. Every time birds fight, she separates them and throws up another little makeshift run and box of some kind for a coop for the bullies or bullied. This spring we are going over there, ripping everything down and building her a proper coop. Big enough for everyone and a real run.
But, in the meantime, visions of her setup ran through our heads all the while we were planning and building our own coop. We wanted something neat and tastful and nice to look at but still big enough and practical. If you notice, the little elevated run area to the far left side in the picture I put up is a raised quail pen that we had to add on after we'd finished the coop. Literally the DAY we finished putting the fencing up on the coop and put our 2wk old chicks out in their new home for the first time, a friend of ours showed up with a dog kennel full of excess quail and chukkars he gotten somewhere. He put them in the coop and half of the immediately squeezed through the fencing and took off. We caught the remaining ones and as hasitly and tastefully as possible added that little "apartment" onto the main chicken coop.
Then a short few weeks later thanks to the wonderful magic of Chicken Math, our 3 to 5 pullets turned into 5 cockerels and 9 pullets. So we needed to expand the coop we'd been adamant on leaving exactly how we'd planned and built it. If you look on the ground just below the "Quail Apartment" on the left you'll notice a couple of post holes I'd dug before the ground froze with the intention of adding onto the run and extending it down to the chain link fence at the bottom of the yard. Then it got cold and enclosing the existing run became priority. So we took unfinished molding, stained it with the same water seal we'd used on the coop and carefully put the plastic up. We'll be able to remove it and re use the molding each year. Next year I plan on making some kind of brackets to slide the molding pieces into so we don't have to keep nailing or stapling them up each year and adding more and more holes to the 4X4 posts.
Yea, I am on the same boat with intentions to add add add! I quickly had to build that new run because although my flock didn't grow in numbers, it quickly grew in physical size. Now I want more birds and even goats but I think I'm going to stay where I'm at now for a little while