Dont have pictures unfortunately (at least that I can post as they are still undeveloped from about 9 years ago ) but I converted a Sauder Armoire into a viv for our 4' Iguana when we had her
Cut out the sides and reinforced all corners with 1/4 round moldings. in the side cutouts I recessed the edges 1/8 inch so that we could put in heavy guage fiberglass screening and on the other plexi. recessed them both and then added 1/2 round molding to cover it. The actual cut out we did the same on the inside edges for look. We did the same to the doors leaving 2" all the way around and putting plexi in as well.
We hinged the top and put in the fiberglass screening under it covering the entire top and then adjustable spring hinges on the top so that we could open or close it amounts to help regulate the heat and air flow
The cardboard back was swapped out for 1/2 inch plywood (heavy but able to hold the shelves built into it)
We added 4 levels staggerd bottom to top
It was 4' X 4' X 6' and when don weightd a TON but was really nice. Sold it with Kay Star when we had to sell her
Armoire was free - from our basement from my parents basement and the other materials were under 100.00