When I say "pull", I mean pulling air - which results in heat being drawn with it.
I have a bunch of heatsinks from past electronics/computer projects. Fashioning a heatsink for the ESC wouldn't be hard at all - maintaining the warranty on the ESC after fitting on a custom heatsink would be. :) Even so, I might attempt to affix a larger heatsink to my ESC (when I get one) anyway.
Speaking of heatsinks, does anyone use thermal compound between the motor heatsink and the motor? Something like Arctic Silver or even cheapie
RadioShack stuff.
Oh, and nbcaznmaster, yeah a larger heatsink would add weight, but as much as a regular heatsink, fan, and associated wiring? ;)