I believe Mtronics did a brushless tank type esc a while back, it was like two esc's with a main controler. the last time i looked i didn't see it, but one might pop up on Ebay or something
Work because i gotta, play because i wanna
People here hate Nitro, I love it. I start it, run it about 50 ft from me and it dies, I go after it. Perfect exercise
I'm not an expert so I won't recommend a motor but have you tried looking into the robot website? Many battle bots are heavier and faster and use skid steering.