So, I was traveling from Copenhagen to New Delhi and needed to bring along my OT, A4 and MD. It all had to be checked baggage because of size and weight, so I decided to make them their own little "suitcase".
This can all be done with a laser cutter able to handle sizes of minimum 600 x 400 mm. If you have a Fablab around, the cost is only some time and wood, boom. NB. this is for 4mm thick material. If you are using another material, you HAVE to make a new print file from Boxmaker - otherwise it won't work.
Here's the measurements for the outer transport box: