Hello - If you live in a large city, your best bet is to have a rep from your local supplier come out and take measurements and supply you with what you need. I'm sure there are some options for customization in the way of size and material options. Our local supplier in Austin is BMC (BuildwithBMC.com). They may be able to ship a unit to you if you give them the opening size of the door, but as it is tricky to get this done correctly, would highly recommend finding a local supplier of doors, door hardware, lumber and mill work products and services and just have them take care of everything for you if at all possible. Hope this helps!