These are “Amalgamod” cases, made by a friend of mine in Melbourne, Australia.
Absolutely excellent cases. I’ve got several 12U folders, and the 6U one pictured above. Can’t recommend them highly enough.
Various Muffs threads on these, e.g. :
https://www.muffwiggler.com/forum/viewtopic.php?t=87542
The cases can be a little hard to get - he does small runs at present, and they sell quickly - but totally worth the wait and investment. Surprisingly fast and cost effective to ship internationally too.
Drop Ian a line via the contact page on his web site (which is otherwise devoid of info!) if you’re interested.
http://www.amalgamod.com/contact/