I can give you the specs and advice etc. And things I would do differently (like wire on the INSIDE instead of the outside). The expense isn't as awful as one would think--- just a little more than a screened porch would be.
The materials are different--untreated lumber, heavy gauge ungalvanized/coated wire and a clear corrugated clear poly top.
I'm renting now, and I'm up to my ears in pets, but it's on a 'someday' list, when I am in a place where I could design such a thing.