To show their support for open source projects, the plan for the HiFiBerry case itself is open source. It can downloaded here: HiFiBerry case design file. Using this postscript file, you should be able to produce the case on a laser cutter near you. Local Fablabs and similar places often have laser cutters available. The design is free for personal, non-commercial use. If you want to sell these enclosures, you will require a license from HiFi berry.
Please note, the case is not compatible with the Raspberry Pi B+ and HiFiBerryDAC+. A version for this will be available soon!