[JThiessen]

I have never really had much experience with them, but they do make some 4 stroke motors for RC. Those might prove to be more reliable in start up and running than the more common 2 cycle nitro's....

Have you looked at the hydrogen powered RC? Search Youtube - there was also a thread on here for it a month or so back.

I wouldn't get so wrapped up in the details of the chassis at this this point. Make up a test bed for your power system - get it configured and tested, then pick your rolling chassis based on the size requirements. You might find it easier to go bigger scale here - 1/5th or larger.