a feigao XL would work nicely if you've corrected your gearing. i use an 8XL sometimes in my FLM-Maxx which weighs about 12 pounds and i can run it through a whole pack without overheating. they're incredibly powerful 2 pole motors, but need to be geared on the low side to stay cool.
http://www.offshoreelectrics.com/pro...prod=fei-540XL