Paul Adam has written a couple of mysteries set in Italy that I really enjoyed. It was about a crime solving violin repairman. The Rinaldi Quartet and Paganini's Ghost (the latter is perhaps a bit too Davinci-codeish in places, but I liked it).
Also, Kristine Kathryn Rusch has a series of mysteries mostly set on the Moon. The Retrieval Artist series.
And if you like historical mysteries, there's a zillion of them set in Rome. Lindsey Davis in particular.
In a similar vein, there's an interesting series by Peter Tremayne set in Ancient Ireland.