I bought the "New Rain 320A waterproof brushed ESC" from ebay for $10.44. It is listed as 60A continous current and has a sizable heat sink. I soldered a 1000uF capacitor on the battery leads close to the ESC to help keep it cool, and it has so far been very good. It runs extremely cool even in tall grass. I put 6 batteries through it so far and it was never more than warm to the touch, I'd say around 100F (38C).
For $10, surely it's worth a shot. It takes around two weeks to come from china though.