Case I want to use is quite low, stock Odroid cooler won't fit (without modifications).
I found a 38x80mm radiator (from a dead motherboard), half of it was covered with a 1mm thick copper shim:
Cooler after cutting the shim in half, all parts are held together with a thermal glue:
Original mount points are used:
And finished cooler attached:
SoC is the only part of Odroid touching the cooler, just like in original design.
Thermal surface shuold be big enough to be used without a fan (Odroid-U3 has a smaller one) but since there will be almost no airflow in the case there will be one.