Milled an old pentium heatsink to cool my Pi and was concerned it might short something out so made this little guard to provide a more stable platform around the CPU, assorted holes around it to clear the tiny surface mount components around the CPU etc so it should touch nothing but the PCB, total thickness is designed to be 2.4mm and the CPU thickness is 2.5mm. My print came out at 2.49mm anyway.

Let me know if you want a thinner one, was considering it so I could put some adhesive foam under it but I don't think its needed.
I doubt anyone wants it but the version marked with "lip" is to suit the heatsink I have and ensure it wont touch the GPIO header pins.

Added the modified case top I used with a large hole so the heatsink sits through it.
I used a mill but there are only cutouts that could be done with a hacksaw, this heatsink was 60mm x approx 55mm, one fine was taller than the others, this fin was cut away entirely with a hacksaw making the heatsink 60mm x 48.6mm, then a small cutaway in one corner to clear the 4 pin J14 PoE header, mine was 8.2x 8.8mm, then a larger cutaway to clear the camera header and 3.5mm jack that is around 22mm square,

A 4 thread sysbench test peaks temperature at 62C with this heatsink, so no need for a fan.