I'd be very surprised if you can't find Rodenbach in Italy. I would think that you'll be able to find lambic as well. If you can't, or even if you can, there are some great Italian craft beers, although like everything in Italy, they are expensive. Since you mentioned Rodenbach, I'd suggest trying Panil Bariquee. It's an Italian take on Flanders Red and one of my favorite examples of the style. Check out ratebeer to find a shop or bar near you.