Traveling by motorcycle

While I don't find exactly what you're asking for, there is a rental agency that has some of the Can Am three wheelers-I see one in Zurich. I'm not sure how common side-cars are in Europe, much less if they are available for rental. The Can Am has some great features. There are, of course, lots of places to rent conventional two wheelers in Italy, though if it were me I'd be tempted by the side-car/three wheel idea too.

http://www.bosenberg.com/

http://it.mototouring.com/noleggio-moto/noleggio-sidecar-e-auto-d-epoca/auto-d-epoca-e-sidecar/?id=61

At a chez per price in Salerno you have this:
http://www.penisolarent.com/it/noleggio-scooter-sorrento.php