This is a remix of two things:

1) The excellent RPI4 case - https://www.thingiverse.com/thing:3793664

and

2) The very capable DIN rail clip - https://www.thingiverse.com/thing:3531692

rpi4_din_bottom.stl is an exact copy of BOTTOM_BLANK.STL found in (1) and the clip is scaled a little to fit the case bottom and the DIN rail better. (I didn't bother with the honeycomb bottom, but it would be easy to do). Any of the tops found in (1) should work.

rpi_din_bottom_M3_inserts.stl is modified to accept brass M3 screw inserts, so that the top can be secured easily; just because I had M3 screws and inserts from a previous project.