Dave,
Last year, I do recall Guy Apple renting an Audi Wagon. Last October, I had a small SUV. When renting overseas, AVIS and other US agencies require that full insurance be taken and the rental is PAID IN ADVANCE. I waited and took a chance by renting in Rome and picking up my car in Rome at the Vatican AVIS office. The deal was better by 100 euros too. It was a bit tricky finding my way out of Rome and onto their freeway system. (Jamie Swan had a heckuva time getting his bearings in Firenze)
AVIS also has mini-vans available but they're not cheap, about 1000 euro for 10 days use.
My plan this year is flying into Rome and picking up a similar vehicle at the airport. From there, it is an easy ride to the Autostrade. Gaiole is about a 2.5 hour drive from Rome. I will only go with a van if I wind up carpooling with others.
Good Luck
Mike Schmidt
Stirling, NJ
USA