Binary package hint: qt4-doc
The qt4-doc package is expected to contain the demos and examples such that they can be executed and tried out immediately. However, the demo sources are installed as a tarball at /usr/share/doc/qt4-doc/qt4-demos.tar.gz and the example sources at /usr/share/doc/qt4-doc/qt4-examples.tar.gz.
In contrast, the default Qt 4 compile using ./configure, make does compile these packages and presumably make install would install the demos and examples in binary form. (I didn't try make install for fear of mucking up my debianised install.)
Therefore I submit that the Qt 4 demos and examples should be provided in compiled form in the qt4-doc package or maybe as two separate binary packages - qt4-demos and qt4-examples (or maybe qt4-demos-and-examples). The sources of course should be included with the qt4-doc package since they are meant for learning Qt but preferrably do NOT ship them in tarballs. The deb format already tar-gz-es the data so there is no space gain.
Just in case some other files are not compiled by the debianised package, I herewith attach some files that may help in identifying such errors. I realize what I have supplied is overkill but I felt like doing it since I don't want Kubuntu's Qt packages to be in any way crippled.