There is an ideal dynamic size for a community having to do with familiarity of face and habitual routine. The average person can stay mindful of about one hundred others without becoming overloaded with memory management. The community should have a varied interest spread among the inhabitants, and a kind of zeal motivation. Really large societies create their own choice buffer by virtue of many, many options for association and personality destinations. A smaller, more intimate society has to be more subservient to restrictive guidelines to be successful.
Society IS the ultimate machine.
Without a rational basis, the elaborate technology required to make the colony functional is beside the point. My unique idea would be to set up an elaborate virtual place facility in the Mars Colony in which the inhabitants could occasionally leave and go someplace else. This soft facility will be the single most difficult item to acquire funding for, balanced against efficient project costs.