Thanks Tobias,
the "Adding New Custom Wizards":http://doc.qt.nokia.com/qtcreator-2.4/creator-project-wizards.html page is exactly what I was looking for.
Moreover, I was looking it exactly for this reason: "If you have a team working on a large application or several applications, you might want to standardize the way the team members create projects and classes." (excerpt taken from the mentioned page). I have to write a few strongly-related applications and I hoped to find a way to standardize the development process.
Most likely, I will just use templates. In any case, the possibility to use generator scripts is an interesting plus.
I'm not going to build binaries for new (different) platforms so I'm not going to touch the mkspecs files (at least, not for now).
BTW: qmake is fine for me, at least for the moment. For more complex needs, I already had a look at cmake, scons and qbs. I will not run out of alternatives... :-)
Your new Qt Build System (qbs) seems to be very smart and very promising. Thanks for having developed it (even if, maybe, a new build system was not the most urgent need of Qt...).
Thanks again.