Committed to liquid cooling

[DrKnow65]

I think the first thing I'll try is a liquid heat sink that attaches (in mirror) to the MMM's heat sink. Then put that whole assembly in some foam tucked into a lightweight watertight case (without the MMM's plastic case) that with any luck shouldn't be too much larger than the MMM with it's fan...

The motor cooling was more about helping HOT motors without using a fan. Like these goofy SC trucks trying to put out 1500 watts on 2S.
I think if you had the ESC as the first component in the loop it would work, assuming the chassis has enough thermal mass to dissipate the combined heat, and like Harold said the motor can be a little hotter.