Here are some sources for ideas. There are more but this should give you an idea of whats out there and the price.

http://www.boaphileplastics.com/

http://pvccages.com/ (I have one of these for my gtp and love it)

http://www.repti-racks.com/

http://www.apcages.com/home/

http://cserpents.com/C_Serpents_Hot_Box/HOME.html