Re: Nick & ETI - Could another large planet in a nearby orbit -
I guess the analogue would be Io, which has both tectonic and volcanic mountains.
You would need a larger Moon, of course, so that it could hold its atmosphere and hydrosphere, but orbit around a close Jovian (itself in the habitable zone) seems to do the trick.
Life would be a bit crazy on such a Moon, by our standards, but liveable. (once you allow for the radiation cloud likely around the Gas Giant)