Both David and Bernhard consider a qdbus binary being available for the N900 a interesting tool for problem diagnosis. Especially for external people who have the skills to use some commands on the N900 itself, but do not have time or skill to set up a remote connection for dbus with akonadi_rds (as this requires a desktop, a connection to the desktop and a desktop user with the right id). http://lists.trolltech.com/pipermail/qt-maemo-feedback/2010-February/000070.html
qdbus is available in the extras section of file.kolab.org/local/maemo with apt-get install qdbus you should be able to install the application
According to http://files.kolab.org/local/maemo/dists/fremantle/extras/binary-armel/Packages there is no qdbus package in the extras section of files.kolab.org/local/maemo
I dropped all libqt4-experimental packages from files.kolab.org/local/maemo extras. Providing a new dbus package for libqt4 would require some work. Maybe it's better to report this upstream.