470kv is too fast. I suppose you want to use this motor because it's small, right? But then if you are going to add gears, your setup will still end up big and heavy. I think, going for hub motors would be a better approach, just like what vanarian is doing.
Or...you can go for a friction drive. Sort of like this video but with urethane wheels.
[youtube]MipbUpBXwFw[/youtube]
You can use this motor for a hub or friction-drive setup: http://www.hobbyking.com/hobbyking/store/__18181__Turnigy_Aerodrive_SK3_6364_190kv_Brushless_Outrunner_Motor.html
This motor is not as long as the motor I'm using. Two of these, one for each foot will get you going. Try 4s batteries first because you might fly away with more.
Also, you will need more than 20A ESC, more than 65A because the motor can max around that. The ESC you linked is also for Heli, it does not have brakes like a car ESC does. If you need the motors to do the braking too, you need a car ESC.
Here's a link from Sk8norcal's blog. I'm in there somewhere, lol.
http://wackyboards.blogspot.com/search/label/%7E%7Ewacky-rollerskate-motorized