The Vallelunga Ceramic company is located near the town of Viterbo, Italy; about 1 hour north of Rome on Highway 2 (see map). While I have not yet written to them, I believe they can be reached by e-mail at ceramica@sirnet.it. I believe this is the e-mail of a ceramics association that has many member companies, so make sure you specify that any e-mail is for Ceramica Vallelunga.
While on my trip to Italy in July 1996, we were specifically looking for the Vallelunga Race Track. We exited the autostrada at Orte to take highway 2 to the race track. Near Viterbo we were elated to find a sign for Ceramica Vallelunga (see photo). I had known this company existed from my searches on the web, but I was unsure of its location and was not even thinking about finding it. Stumbling onto it's location was a very pleasant surprise.
We took the short detour to the actual plant but unfortunately, it was on a Saturday, therefore the place was closed and the front gate was locked. Apparently someone was in there because the side gate was open. We decided to walk in and take a look around. We were surrounded by large pallets of tile, all boxed and wrapped in plastic, ready to ship (see below photo; click to see larger version). 
We searched extensively for some souvenir, such as an empty box, but the place was spotless with no sign of any empty boxes. I was tempted to take a box of tile as a souvenir, but didn't cherish the idea of lugging a 100 pound box of tile to the airport. I did find one broken piece of tile and had to settle for that as my souvenir. My wife, Lene, went snooping around the outside of the office and peered inside. There she saw a few good souvenirs such as a Ceramica Vallelunga calendar. Maybe one of these days I'll get one. She also took the photo of their logo, of which you see a slightly modified version above. We wandered around for a while but did not see anybody; not that it would have done much good since neither of us speak Italian. Besides, we were headed to the Vallelunga Race Track and it was getting late. We had to settle for the one broken piece of tile and the photos you see here.
Some months later, and back in Northern California, we were informed by a friend whose husband makes deliveries, that he recently delivered several boxes of Ceramica Vallelunga tiles to a local address. So I guess it is possible to purchase these tiles in the USA. I called around to a few ceramic tile stores, but so far, have had no luck finding anybody that carries this brand. I will keep looking and post any findings.