Yes just the executable file and .desktop file are needed to make the home screen widget.

But i would advise using scratchbox to compile as i was having major issues with getting it running when compiling with madde on windows.

I am no expert here but i think you NEED to use the base code from there example as it interfaces with X11.

Also i had to edit the examples .pro file by moving the include(qmaemo5homescreenadaptor.pri)
to the line below the template=app.

you may have read that you need the qt plugin loader to load qt home screen apps this is still true and you can get it by installing the qt4-homescreen-example as it is a dependancie. or i think you can install the plugin loader from atp-get.