I've got a CMake based project with the following "design":
add_subdirectory(first_lib)
add_subdirectory(second_lib)
add_subdirectory(qt_application)
My question is - can I create a qt_application subproject as a qmake based? I think it will be much easier.
It it is impossible - how can I manage it in other way?
CMake is perfectly capable of building a Qt project. All of KDE uses CMake.
See Qt's documentation.