Power equirements for a pilot or odessey are alot more because of the weight. I'd keep it simple with a kart. There are alot out there with indepedent front suspension and a swingarm rear setup that won't beat you to death and weigh about half as much as a odessey. Kart would be simpler to convert too. Odessey does have brakes up front and more rollover protection than a kart though.
http://www.youtube.com/watch?v=MSiz_KE2XAo