I just picked up my terrarium yesterday. The person I bought it from was very helpful and accomodating in customizing it to my exact specifications.
For racks, I like something plain and simple. If gave you a rubbermaid container, and told you that I would need rack to fit 8 of those containers, you should be able to do that. Also, it would be helpful if your racks came prewired with heat tape etc.
For enclosures, I am more fussy about its looks, as it will be in my living/dining room. I personally like maple and oak, but any type of wood (except cedar) is OK too.
Pricing for racks should be fairly cheap, in the $150-200 range, like Zhakrin mentioned, unless the customer wants them for display purposes. Enclosures would be highly dependent on the type of materials you use, size, features etc. I would like to see plain vanilla melamine 6x2x2 cages for about $200-300, and those using oak or maple for around $600+.
Hope this helps. Do you have any pictures of your completed cages?