Ive had my Ig for a year now. I built his cage using 2x4's plywood and mesh but had problems with humidity so I decided to upgrade. Im reusing most of the frame work from the old cage so I decided to build him a temporary one out of PVC. Its not hard to build and not too expensive plus can double as an outdoor enclosure once I finish my upgrade.

I bumped onto this website:
http://www.atombum.com/cazicsplace/index.htm
Im using some ideas from there for the new enclosure. Maybe you can get some ideas from there too. Just be aware it can get expensive. Happy building.