Thanks for the vote of confidence, Lob, but unfortunately I can't help much on this one. As I noted in this post in the Cycling in Switzerland thread, the main national bike rental company, Rent-A-Bike, doesn't rent road bikes. Therefore, your best bet is a local bike store or finding someone who has a spare bike (i.e., Salsa Lover). I'd know of a shop to try near Lausanne, but I have no idea about Zurich, sorry. If you do get a hold of a bike, make sure that your friend brings his/her pedals as well as shoes to ensure compatibility.