The Root 4 has a branch on Github which supports the 1’1/2 inch (38.1mm) box section.
The link to the files are HERE
As I’ve not built one, nor heard any feedback from the anyone who’s built it. The 1’1/2 variant will stay in development until I’ve heard they fit for purpose. I strongly believe the parts are perfectly fine but I would like to have confirmation.
Additionally, this variant supports the standard side panel and Z axis plates which can be brought form the shop.