Junkman: The heat on the bottom of the ESC is probably the BEC circuit because you are running 3s. To be sure, temporarily disable the BEC and use an Rx pack and feel the heat. I bet it will be gone.
asheck: What about
this ESC? 200A @ up to 7S. Lower price if you feel like taking a chance. Supposedly works with pistol grip radios if the review is accurate.