I built this to mount my RackPi 2HE Rackmount for Blackmagic Design Micro Converter 3G/12G to a Jib, Tripod Leg or Camera Cage but it should work with other RackPi style Equipment for DAP MP-1 Rack (Opening: 68mm x 39mm)

Designed to print without Supports, therefore the center hole is rectangular but fits a long ¼'' Screw for Cage mounting.
PipeAdapter can be used to fit to round mount points like Pipes or Tripod Legs and secured with Velcro or zip ties. This is untested and might require a glued rubber pad or print in TPU to prevent slip.

This Solution is not the most space efficient but designed to keep the Gear in the Rackmount holders while mounted somewhere else.

Hope to see your Makes :)