This little monster is a Corne case by SirFodds/MrFodds. It's not simply unibody but also features a magnetic centerpiece and an optional number row add-on.
Features
Gasket or plate mounting
Removable magnetic center-piece to hold the two halves in place
DXF file for the key plate to allow CNC / laser cutting in a material of your choice (designed for 1.5mm plate thickness)
Optional legs to provide a 10 degree angle
The legs are required if you plan to use the center piece, as it is designed around this angle.
The extra number row is handwired, running off a separate controller.
With regards to the gaskets:
It's designed for a 1.5mm thick plate, with 1.5-2mm thick Poron gasket material (Thickness depends on how much retention you want in the gasket. Thicker will feel firmer, thinner will have more give) – SirFodds.
The files are for printing the right hand of the keyboard. To print the left half, take every file other than "centre.stl" and mirror before printing.