This Module is currently available.
4HP Blank Panel
by Isobar Industries 4HP Blank Eurorack Panel. White silkscreen on black PCB.
https://isobarindustries.etsy.com/listing/1530773013/overgrowth-2-4hp-eurorack-blank-panel
These merchants probably sell this module. Huh?
Included in 21 Racks, 10 are public: