All the linked products are pre-built and defined items. We're not trying to get a fully custom made case, just a bulk order of an existing case design that is already up for sale by some custom case makers. What options we'll get as far as button layout/paint/etc I'm not sure and will likely depend on the builder.
Someone suggested contacting razer to see if they had extra stock of their atrox cases. Would be interesting to see if they would do a mass sell off of just the case.