why not just use plastic housing for now and move up later? that's another option. but I'm curious why it is that you would want a custom cage. There are many great cages available for boas that I wouldn't think there would be a huge need for a custom job. But if you have something particular in mind then i could see why you might want it, but there are so many options available as standard that you might want to research cages. besides those listed already you should check out animal plastics.