As far as I understand qmake processes a .pro file to generate the Makefile used to build the actual qt application.
That said, how can I let qmake generate a Makefile with some custom Makefile target?
Specifically I'd like to have in the Makefile a target called "package" that will run all the steps required to create the package for my freshly compiled qt application
Try using "QMAKE_EXTRA_TARGETS" as described in The Power of QMake.