Adapted the Iris middle layer from monsieurtaco to fit the printed legs and mount from coddingtonbear's TS65 Split Mechanical.
Print one left layer, one right layer, 6x inserts, 6x legs, and 6x feet. Assemble using M3 screws (more on that below).
3D Solutech PLA
I also sliced it into 4 pieces and glued them together afterwards, since the i3 Mini's print bed isn't big enough. Still functional.
Might or might not need supports, depending on how good your printer is at bridging the square indentations that the mount inserts fill.
Hardware required, 3x each side: M3x16 screws, nuts, washers, and (optionally) lock washers. The lock washers act as a spring: Tighten it down all the way and it won't budge, loosen it a bit and you can adjust the leg position with some force.
If you don't use the lock washer, might want a shorter screw. The extra washer in this case is used as a spacer to prevent the screw from going too far into the case and applying undesired pressure to the board.
The mount point is provided as a square insert because my printer was only able to print its texture in fine enough detail when that texture was pointed upward. This also lets you rotate the insert to get different angles.
Models for both 12mm and 17mm tall inner layers. I socketed the Pro Micro on my v2.5 board, to be able to replace it without resoldering, and needed the extra thickness.
Sliced and diced with Microsoft 3D Builder. Including 3mf files alongside the stl files if you'd like to tinker further.