Kayak.com does a pretty good job with rental cars, it seems. When you select "drop off at another location" it gives you a different city, of course. Useful tip: Say you're picking up a car in Florence. When you enter Florence, it sort of assumes you mean the main airport so it says FLR. Scroll down, and you'll see the choice "Florence, Italy" with no airport symbol. If you choose that choice, you get ALL the rental locations in Florence, including the ones in town. I don't want to Schlep out to the airport to get a car, I want to get one at Via Maso Finiguerra 33. Well, doing this and scrolling down the list you find that location. Same is true of your drop off. I'm finding that when I'm looking to pick up in Florence and drop in Milan, Hertz is the best deal at about $70 a day for one size above "Clown car" Oh, if you want the car for two days it costs the same as three days when you're dropping in another city.
Ted, Please find the best rate you can on Kayak and then call AutoEurope. They will beat or match the best rate you can find, and are renowned for their customer service. There was no difference in charge to drop off in a different city. I paid less than US$150 for a 3 day rental for the smallest car (or 2nd smallest - can't remember), but with the no deductible CDW. I'm picking up in Pisa (not at the airport) and dropping off in Rome (near the Borghese Gallery).