So looking through Craigslist in my area I found a guy selling old Jewelry display cases. They look like perfect ready to cages. Some already have electric built in. Only challenge may be access from the rear but some did have front sliding doors already.
Example
http://evansville.craigslist.org/for/3226162613.html
Example
http://evansville.craigslist.org/for/3226162613.html