Rapid proto-typing service that can make practically anything using any method you wish. If you just want it made, they can do it.
One of the more established 3D-printing services. If you don't have a crazy 3D-printer, they do.
If you want to move away from 3D printing into more traditional enclosure making, or other things that require injection-molding, this company offers a similar low-quantity service. Not that cheap, but nothing is (that I've seen yet) is in that arena.