Might I suggest Salerno as the site of the event, I am president of the Linux Users Group of the University of Salerno and I've already made them several events, I am also part of the Italian KDE users community (kdeitalia.it) and I have contacts with the Italian QT users community (qt-italia.org). The event could be done within the medieval Castle of Salerno, which offers a picturesque backdrop, and a conference hall inaugurated for less than 6 months.