I still think just incorporating your ideas into an extra-cycle is what you really want... But your got me curious now.

Tell you what, if you build this, I am very much looking forward to seeing pictures and reports from your ride. I've seen and heard people touring on penny farthings, recumbents, single speed, guy pulling a red child's wagon, 10 grand bicycles, Walmart bicycles (like me) and of course tandems but with 2 people riding it. Don't know if a unicycle has been done though.... Be interesting to read about your experiences.