Yeah, I was looking around today and it seams no one has any product support for it yet. I was hoping for this to come to life as I've been wanting to build an AR15 in 6mm.
First Spear makes a 43" case that might work, it's a no thrills made in the USA bag with lots of room.
https://www.first-spear.com/packs-bags/weapon-cases/arms-case