Do your future plans involve flying with all three guitars after the flight to Italy? Or will you be more likely to take only one guitar and leave the other two in Italy on subsequent trips? If the latter is the case (no pun intended) I would buy one good case of the Calton, Anvil, Mark Leaf class and build sturdy shipping crates for the other two. Of course, if the three guitars are of very different sizes (Say a D an OM and a big J) you'd have to order the case to fit one of them and the other two would get jealous.

Bruce