A live gunboat I/T, where I played the T side of the alliance: http://webdiplomacy.net/board.php?
gameID=168897#gamePanel. As I recall, this alliance arose in response to a strong Austria, and was then sustained by the threat of an English solo. As Turkey, I kept just one Mediterranean fleet parked in the Aegean Sea, which kept me well enough defended, and also seemed to be adequate assurance to Italy that I wasn't going to attack him.
However, it bears mentioning that I had to scroll through five pages of my games to find even a single example of long-term I/T cooperation. I/T relations in the vast majority of my games consist of total hostility between both nations in the Balkans & Med. In an I/T war, my sense is that the nation which can hold Serbia prevails over 90% of the time.